121564161 has 12 divisors (see below), whose sum is σ = 185921892. Its totient is φ = 76275456.

The previous prime is 121564153. The next prime is 121564189. The reversal of 121564161 is 161465121.

121564161 is a `hidden beast` number, since 1 + 2 + 15 + 641 + 6 + 1 = 666.

It can be written as a sum of positive squares in 2 ways, for example, as 40564161 + 81000000 = 6369^2 + 9000^2 .

It is not a de Polignac number, because 121564161 - 2³ = 121564153 is a prime.

It is not an unprimeable number, because it can be changed into a prime (121564061) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 397116 + ... + 397421.

It is an arithmetic number, because the mean of its divisors is an integer number (15493491).

Almost surely, 2^121564161 is an apocalyptic number.

It is an amenable number.

121564161 is a deficient number, since it is larger than the sum of its proper divisors (64357731).

121564161 is a wasteful number, since it uses less digits than its factorization.

121564161 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 794560 (or 794557 counting only the distinct ones).

The product of its digits is 1440, while the sum is 27.

The square root of 121564161 is about 11025.6138604615. The cubic root of 121564161 is about 495.3762551010.

The spelling of 121564161 in words is "one hundred twenty-one million, five hundred sixty-four thousand, one hundred sixty-one".