36644655681 has 24 divisors (see below), whose sum is σ = 54586509120. Its totient is φ = 23677432800.

The previous prime is 36644655647. The next prime is 36644655683. The reversal of 36644655681 is 18655644663.

36644655681 is a `hidden beast` number, since 3 + 6 + 6 + 4 + 4 + 6 + 556 + 81 = 666.

It is not a de Polignac number, because 36644655681 - 2⁶ = 36644655617 is a prime.

It is a super-2 number, since 2×36644655681² (a number of 22 digits) contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (36644655683) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 448290 + ... + 523691.

It is an arithmetic number, because the mean of its divisors is an integer number (2274437880).

Almost surely, 2^36644655681 is an apocalyptic number.

It is an amenable number.

36644655681 is a deficient number, since it is larger than the sum of its proper divisors (17941853439).

36644655681 is a wasteful number, since it uses less digits than its factorization.

36644655681 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 972117 (or 972114 counting only the distinct ones).

The product of its digits is 12441600, while the sum is 54.

The spelling of 36644655681 in words is "thirty-six billion, six hundred forty-four million, six hundred fifty-five thousand, six hundred eighty-one".