628909 has 2 divisors, whose sum is σ = 628910. Its totient is φ = 628908.

The previous prime is 628877. The next prime is 628913. The reversal of 628909 is 909826.

628909 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 426409 + 202500 = 653^2 + 450^2 .

It is a cyclic number.

It is not a de Polignac number, because 628909 - 2⁵ = 628877 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (628939) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 314454 + 314455.

It is an arithmetic number, because the mean of its divisors is an integer number (314455).

2⁶²⁸⁹⁰⁹ is an apocalyptic number.

It is an amenable number.

628909 is a deficient number, since it is larger than the sum of its proper divisors (1).

628909 is an equidigital number, since it uses as much as digits as its factorization.

628909 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 7776, while the sum is 34.

The square root of 628909 is about 793.0378301191. The cubic root of 628909 is about 85.6766749012.

The spelling of 628909 in words is "six hundred twenty-eight thousand, nine hundred nine".