Is the word cento the same in Brazilian and European Portuguese?

No.

While the spelling, grammar, and the numerical meaning (as part of larger numbers like 101 or 120) are identical, there is a difference in typical usage and pronunciation. In Brazil, "um cento" is a common commercial unit used to refer to a specific package of 100 items, particularly food (e.g., "um cento de salgadinhos"). In Portugal, while the word is understood, people are much more likely to use the number "cem" or the word "centena" to express quantity. Furthermore, in Brazil, "cento" is often used colloquially to denote a high speed (e.g., "a cento por hora"), whereas in Portugal, "cem" is the standard. Finally, the pronunciation differs significantly: in Brazil, the "e" is clearly pronounced and the "t" is dental/alveolar, while in Portugal, the "e" is often reduced to a nearly silent, closed vowel.

Brazilian Portuguese Examples

1. "Vou encomendar um cento de salgadinhos para a festa." (I am going to order a hundred savory snacks for the party.)
2. "O carro estava correndo a cento por hora." (The car was speeding at a hundred per hour.)
3. "Ele tem cento e vinte anos." (He is one hundred and twenty years old.)
4. "Comprei um cento de brigadeiros para o aniversário." (I bought a hundred/a set of 100 brigadeiros for the birthday.)
5. "A conta do restaurante deu cento e cinquenta reais." (The restaurant bill came to one hundred and fifty reais.)

Portuguese Examples

1. "Vou encomendar cem salgadinhos para a festa." (I am going to order one hundred savory snacks for the party.)
2. "O carro ia a cem por hora." (The car was going at a hundred per hour.)
3. "Ele tem cento e vinte anos." (He is one hundred and twenty years old.)
4. "Comprei uma centena de doces para o aniversário." (I bought a hundred sweets for the birthday.)
5. "A conta do restaurante deu cento e cinquenta euros." (The restaurant bill came to one hundred and fifty euros.)