665661755734856 has 16 divisors (see below), whose sum is σ = 1263153331666800. Its totient is φ = 328820867290384.

The previous prime is 665661755734849. The next prime is 665661755734967. The reversal of 665661755734856 is 658437557166566.

It is a super-2 number, since 2×665661755734856² (a number of 30 digits) contains 22 as substring.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 501251321426 + ... + 501251322753.

It is an arithmetic number, because the mean of its divisors is an integer number (78947083229175).

Almost surely, 2^{665661755734856} is an apocalyptic number.

It is an amenable number.

665661755734856 is a deficient number, since it is larger than the sum of its proper divisors (597491575931944).

665661755734856 is a wasteful number, since it uses less digits than its factorization.

665661755734856 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1002502644268 (or 1002502644264 counting only the distinct ones).

The product of its digits is 22861440000, while the sum is 80.

The spelling of 665661755734856 in words is "six hundred sixty-five trillion, six hundred sixty-one billion, seven hundred fifty-five million, seven hundred thirty-four thousand, eight hundred fifty-six".