643900637516 has 48 divisors (see below), whose sum is σ = 1197937368768. Its totient is φ = 302183481600.

The previous prime is 643900637509. The next prime is 643900637531. The reversal of 643900637516 is 615736009346.

It is a super-2 number, since 2×643900637516² (a number of 24 digits) contains 22 as substring.

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, 2226386 + ... + 2498918.

It is an arithmetic number, because the mean of its divisors is an integer number (24957028516).

Almost surely, 2^643900637516 is an apocalyptic number.

It is an amenable number.

643900637516 is a deficient number, since it is larger than the sum of its proper divisors (554036731252).

643900637516 is a wasteful number, since it uses less digits than its factorization.

643900637516 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 273042 (or 273040 counting only the distinct ones).

The product of its (nonzero) digits is 2449440, while the sum is 50.

The spelling of 643900637516 in words is "six hundred forty-three billion, nine hundred million, six hundred thirty-seven thousand, five hundred sixteen".