665638588715 has 16 divisors (see below), whose sum is σ = 849221610048. Its totient is φ = 499747687296.

The previous prime is 665638588691. The next prime is 665638588723. The reversal of 665638588715 is 517885836566.

It is a cyclic number.

It is not a de Polignac number, because 665638588715 - 2²⁶ = 665571479851 is a prime.

It is a Duffinian 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, 54599204 + ... + 54611393.

It is an arithmetic number, because the mean of its divisors is an integer number (53076350628).

Almost surely, 2^665638588715 is an apocalyptic number.

665638588715 is a deficient number, since it is larger than the sum of its proper divisors (183583021333).

665638588715 is a wasteful number, since it uses less digits than its factorization.

665638588715 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 109210678.

The product of its digits is 290304000, while the sum is 68.

The spelling of 665638588715 in words is "six hundred sixty-five billion, six hundred thirty-eight million, five hundred eighty-eight thousand, seven hundred fifteen".