36161205921 has 21 divisors (see below), whose sum is σ = 54224706049. Its totient is φ = 24104047716.

The previous prime is 36161205901. The next prime is 36161205989. The reversal of 36161205921 is 12950216163.

The square root of 36161205921 is 190161.

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

36161205921 is a `hidden beast` number, since 3 + 6 + 1 + 61 + 2 + 0 + 592 + 1 = 666.

It is a de Polignac number, because none of the positive numbers 2^k-36161205921 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (36161205901) by changing a digit.

It is a polite number, since it can be written in 20 ways as a sum of consecutive naturals, for example, 5130826 + ... + 5137868.

Almost surely, 2^36161205921 is an apocalyptic number.

36161205921 is the 190161-st square number.

36161205921 is the 95081-st centered octagonal number.

It is an amenable number.

36161205921 is a deficient number, since it is larger than the sum of its proper divisors (18063500128).

36161205921 is an frugal number, since it uses more digits than its factorization.

36161205921 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 14104 (or 7046 counting only the distinct ones).

The product of its (nonzero) digits is 19440, while the sum is 36.

Multiplying 36161205921 by its sum of digits (36), we get a square (1301803413156 = 1140966²).

The spelling of 36161205921 in words is "thirty-six billion, one hundred sixty-one million, two hundred five thousand, nine hundred twenty-one".