161560661656 has 16 divisors (see below), whose sum is σ = 304284657600. Its totient is φ = 80418086304.

The previous prime is 161560661621. The next prime is 161560661659. The reversal of 161560661656 is 656166065161.

It is a super-2 number, since 2×161560661656² (a number of 23 digits) contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (161560661659) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 45278671 + ... + 45282238.

It is an arithmetic number, because the mean of its divisors is an integer number (19017791100).

Almost surely, 2^161560661656 is an apocalyptic number.

It is an amenable number.

161560661656 is a deficient number, since it is larger than the sum of its proper divisors (142723995944).

161560661656 is a wasteful number, since it uses less digits than its factorization.

161560661656 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 90561138 (or 90561134 counting only the distinct ones).

The product of its (nonzero) digits is 1166400, while the sum is 49.

The spelling of 161560661656 in words is "one hundred sixty-one billion, five hundred sixty million, six hundred sixty-one thousand, six hundred fifty-six".