628693921 has 2 divisors, whose sum is σ = 628693922. Its totient is φ = 628693920.

The previous prime is 628693913. The next prime is 628693931. The reversal of 628693921 is 129396826.

628693921 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., 626951521 + 1742400 = 25039^2 + 1320^2 .

It is a cyclic number.

It is not a de Polignac number, because 628693921 - 2³ = 628693913 is a prime.

It is not a weakly prime, because it can be changed into another prime (628693931) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 314346960 + 314346961.

It is an arithmetic number, because the mean of its divisors is an integer number (314346961).

Almost surely, 2^628693921 is an apocalyptic number.

It is an amenable number.

628693921 is a deficient number, since it is larger than the sum of its proper divisors (1).

628693921 is an equidigital number, since it uses as much as digits as its factorization.

628693921 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 279936, while the sum is 46.

The square root of 628693921 is about 25073.7695809784. The cubic root of 628693921 is about 856.6690700439.

The spelling of 628693921 in words is "six hundred twenty-eight million, six hundred ninety-three thousand, nine hundred twenty-one".