644258770968 has 32 divisors (see below), whose sum is σ = 1632710588400. Its totient is φ = 211811102208.

The previous prime is 644258770933. The next prime is 644258770979. The reversal of 644258770968 is 869077852446.

It is a happy number.

It is a Smith number, since the sum of its digits (66) coincides with the sum of the digits of its prime factors.

It is a junction number, because it is equal to n+sod(n) for n = 644258770899 and 644258770908.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 183862053 + ... + 183865556.

Almost surely, 2^644258770968 is an apocalyptic number.

It is an amenable number.

644258770968 is an abundant number, since it is smaller than the sum of its proper divisors (988451817432).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

644258770968 is a wasteful number, since it uses less digits than its factorization.

644258770968 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 367727691 (or 367727687 counting only the distinct ones).

The product of its (nonzero) digits is 162570240, while the sum is 66.

The spelling of 644258770968 in words is "six hundred forty-four billion, two hundred fifty-eight million, seven hundred seventy thousand, nine hundred sixty-eight".