628989917 has 2 divisors, whose sum is σ = 628989918. Its totient is φ = 628989916.

The previous prime is 628989887. The next prime is 628989937. The reversal of 628989917 is 719989826.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 555356356 + 73633561 = 23566^2 + 8581^2 .

It is a cyclic number.

It is not a de Polignac number, because 628989917 - 2²⁸ = 360554461 is a prime.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (628989937) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 314494958 + 314494959.

It is an arithmetic number, because the mean of its divisors is an integer number (314494959).

Almost surely, 2^628989917 is an apocalyptic number.

It is an amenable number.

628989917 is a deficient number, since it is larger than the sum of its proper divisors (1).

628989917 is an equidigital number, since it uses as much as digits as its factorization.

628989917 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 3919104, while the sum is 59.

The square root of 628989917 is about 25079.6713893942. The cubic root of 628989917 is about 856.8034920180.

Subtracting 628989917 from its reverse (719989826), we obtain a palindrome (90999909).

The spelling of 628989917 in words is "six hundred twenty-eight million, nine hundred eighty-nine thousand, nine hundred seventeen".