638657220004 has 24 divisors (see below), whose sum is σ = 1122512728568. Its totient is φ = 317942150400.

The previous prime is 638657219939. The next prime is 638657220013. The reversal of 638657220004 is 400022756836.

It can be written as a sum of positive squares in 4 ways, for example, as 35627317504 + 603029902500 = 188752^2 + 776550^2 .

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, 540574 + ... + 1252810.

Almost surely, 2^638657220004 is an apocalyptic number.

It is an amenable number.

638657220004 is a deficient number, since it is larger than the sum of its proper divisors (483855508564).

638657220004 is a wasteful number, since it uses less digits than its factorization.

638657220004 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 713215 (or 713213 counting only the distinct ones).

The product of its (nonzero) digits is 483840, while the sum is 43.

The spelling of 638657220004 in words is "six hundred thirty-eight billion, six hundred fifty-seven million, two hundred twenty thousand, four".