156405221361 has 27 divisors (see below), whose sum is σ = 227275457643. Its totient is φ = 103647660480.

The previous prime is 156405221359. The next prime is 156405221381. The reversal of 156405221361 is 163122504651.

The square root of 156405221361 is 395481.

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

156405221361 is a `hidden beast` number, since 1 + 5 + 64 + 0 + 522 + 13 + 61 = 666.

It can be written as a sum of positive squares in only one way, i.e., 117627734961 + 38777486400 = 342969^2 + 196920^2 .

It is not a de Polignac number, because 156405221361 - 2¹ = 156405221359 is a prime.

It is not an unprimeable number, because it can be changed into a prime (156405221321) by changing a digit.

It is a polite number, since it can be written in 26 ways as a sum of consecutive naturals, for example, 285932490 + ... + 285933036.

Almost surely, 2^156405221361 is an apocalyptic number.

156405221361 is the 395481-st square number.

156405221361 is the 197741-st centered octagonal number.

It is an amenable number.

156405221361 is a deficient number, since it is larger than the sum of its proper divisors (70870236282).

156405221361 is an frugal number, since it uses more digits than its factorization.

156405221361 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1582 (or 791 counting only the distinct ones).

The product of its (nonzero) digits is 43200, while the sum is 36.

Multiplying 156405221361 by its sum of digits (36), we get a square (5630587968996 = 2372886²).

The spelling of 156405221361 in words is "one hundred fifty-six billion, four hundred five million, two hundred twenty-one thousand, three hundred sixty-one".