634720657 has 2 divisors, whose sum is σ = 634720658. Its totient is φ = 634720656.

The previous prime is 634720637. The next prime is 634720679. The reversal of 634720657 is 756027436.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 499254336 + 135466321 = 22344^2 + 11639^2 .

It is a cyclic number.

It is not a de Polignac number, because 634720657 - 2⁷ = 634720529 is a prime.

It is equal to p_33039976 and since 634720657 and 33039976 have the same sum of digits, it is a Honaker prime.

It is not a weakly prime, because it can be changed into another prime (634720637) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 317360328 + 317360329.

It is an arithmetic number, because the mean of its divisors is an integer number (317360329).

Almost surely, 2^634720657 is an apocalyptic number.

It is an amenable number.

634720657 is a deficient number, since it is larger than the sum of its proper divisors (1).

634720657 is an equidigital number, since it uses as much as digits as its factorization.

634720657 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 211680, while the sum is 40.

The square root of 634720657 is about 25193.6630325961. The cubic root of 634720657 is about 859.3977471744.

The spelling of 634720657 in words is "six hundred thirty-four million, seven hundred twenty thousand, six hundred fifty-seven".