628921 has 2 divisors, whose sum is σ = 628922. Its totient is φ = 628920.

The previous prime is 628913. The next prime is 628937. The reversal of 628921 is 129826.

It is a happy number.

628921 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 622521 + 6400 = 789^2 + 80^2 .

It is a cyclic number.

It is not a de Polignac number, because 628921 - 2³ = 628913 is a prime.

It is a nialpdrome in base 15.

It is a self number, because there is not a number n which added to its sum of digits gives 628921.

It is not a weakly prime, because it can be changed into another prime (628021) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 314460 + 314461.

It is an arithmetic number, because the mean of its divisors is an integer number (314461).

2⁶²⁸⁹²¹ is an apocalyptic number.

It is an amenable number.

628921 is a deficient number, since it is larger than the sum of its proper divisors (1).

628921 is an equidigital number, since it uses as much as digits as its factorization.

628921 is an evil number, because the sum of its binary digits is even.

The product of its digits is 1728, while the sum is 28.

The square root of 628921 is about 793.0453959264. The cubic root of 628921 is about 85.6772198203.

The spelling of 628921 in words is "six hundred twenty-eight thousand, nine hundred twenty-one".