644315157 has 6 divisors (see below), whose sum is σ = 930677462. Its totient is φ = 429543432.

The previous prime is 644315153. The next prime is 644315173. The reversal of 644315157 is 751513446.

644315157 is a `hidden beast` number, since 644 + 3 + 1 + 5 + 1 + 5 + 7 = 666.

644315157 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It can be written as a sum of positive squares in only one way, i.e., 445674321 + 198640836 = 21111^2 + 14094^2 .

It is not a de Polignac number, because 644315157 - 2² = 644315153 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (644315153) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 35795278 + ... + 35795295.

Almost surely, 2^644315157 is an apocalyptic number.

It is an amenable number.

644315157 is a deficient number, since it is larger than the sum of its proper divisors (286362305).

644315157 is a wasteful number, since it uses less digits than its factorization.

644315157 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 71590579 (or 71590576 counting only the distinct ones).

The product of its digits is 50400, while the sum is 36.

The square root of 644315157 is about 25383.3637841796. The cubic root of 644315157 is about 863.7063567774.

The spelling of 644315157 in words is "six hundred forty-four million, three hundred fifteen thousand, one hundred fifty-seven".