161591136256 has 117 divisors (see below), whose sum is σ = 355813182039. Its totient is φ = 73321881600.

The previous prime is 161591136229. The next prime is 161591136313. The reversal of 161591136256 is 652631195161.

The square root of 161591136256 is 401984.

It is a perfect power (a square), and thus also a powerful number.

It is a super-2 number, since 2×161591136256² (a number of 23 digits) contains 22 as substring.

It is a Duffinian number.

It is an unprimeable number.

It is a polite number, since it can be written in 8 ways as a sum of consecutive naturals, for example, 282996451 + ... + 282997021.

Almost surely, 2^161591136256 is an apocalyptic number.

161591136256 is a gapful number since it is divisible by the number (16) formed by its first and last digit.

161591136256 is the 401984-th square number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 161591136256

161591136256 is an abundant number, since it is smaller than the sum of its proper divisors (194222045783).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

161591136256 is an frugal number, since it uses more digits than its factorization.

161591136256 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1188 (or 584 counting only the distinct ones).

The product of its digits is 291600, while the sum is 46.

The spelling of 161591136256 in words is "one hundred sixty-one billion, five hundred ninety-one million, one hundred thirty-six thousand, two hundred fifty-six".