638657711461 has 16 divisors (see below), whose sum is σ = 796412510208. Its totient is φ = 497552900400.

The previous prime is 638657711443. The next prime is 638657711519. The reversal of 638657711461 is 164117756836.

It is a cyclic number.

It is not a de Polignac number, because 638657711461 - 2³³ = 630067776869 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (638657711401) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 476325 + ... + 1226458.

It is an arithmetic number, because the mean of its divisors is an integer number (49775781888).

Almost surely, 2^638657711461 is an apocalyptic number.

It is an amenable number.

638657711461 is a deficient number, since it is larger than the sum of its proper divisors (157754798747).

638657711461 is a wasteful number, since it uses less digits than its factorization.

638657711461 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1707672.

The product of its digits is 5080320, while the sum is 55.

The spelling of 638657711461 in words is "six hundred thirty-eight billion, six hundred fifty-seven million, seven hundred eleven thousand, four hundred sixty-one".