656405985801 has 16 divisors (see below), whose sum is σ = 913296597120. Its totient is φ = 418561186560.

The previous prime is 656405985793. The next prime is 656405985817. The reversal of 656405985801 is 108589504656.

It is not a de Polignac number, because 656405985801 - 2³ = 656405985793 is a prime.

It is a super-2 number, since 2×656405985801² (a number of 24 digits) contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (656405985401) 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, 1708035 + ... + 2056743.

It is an arithmetic number, because the mean of its divisors is an integer number (57081037320).

Almost surely, 2^656405985801 is an apocalyptic number.

It is an amenable number.

656405985801 is a deficient number, since it is larger than the sum of its proper divisors (256890611319).

656405985801 is a wasteful number, since it uses less digits than its factorization.

656405985801 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 376016.

The product of its (nonzero) digits is 10368000, while the sum is 57.

The spelling of 656405985801 in words is "six hundred fifty-six billion, four hundred five million, nine hundred eighty-five thousand, eight hundred one".