649591911920 has 80 divisors (see below), whose sum is σ = 1772708795328. Its totient is φ = 216697835520.

The previous prime is 649591911919. The next prime is 649591911931. The reversal of 649591911920 is 29119195946.

It is a tau number, because it is divible by the number of its divisors (80).

It is a Harshad number since it is a multiple of its sum of digits (56).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 15654761 + ... + 15696200.

Almost surely, 2^649591911920 is an apocalyptic number.

It is an amenable number.

649591911920 is an abundant number, since it is smaller than the sum of its proper divisors (1123116883408).

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

649591911920 is a wasteful number, since it uses less digits than its factorization.

649591911920 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 31351018 (or 31351012 counting only the distinct ones).

The product of its (nonzero) digits is 1574640, while the sum is 56.

The spelling of 649591911920 in words is "six hundred forty-nine billion, five hundred ninety-one million, nine hundred eleven thousand, nine hundred twenty".