18864668796921 has 20 divisors (see below), whose sum is σ = 28200220221492. Its totient is φ = 12567669481728.

The previous prime is 18864668796859. The next prime is 18864668796943. The reversal of 18864668796921 is 12969786646881.

18864668796921 is a `hidden beast` number, since 1 + 8 + 8 + 6 + 466 + 8 + 79 + 69 + 21 = 666.

It can be written as a sum of positive squares in 2 ways, for example, as 5799480220521 + 13065188576400 = 2408211^2 + 3614580^2 .

It is not a de Polignac number, because 18864668796921 - 2⁹ = 18864668796409 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (81).

It is not an unprimeable number, because it can be changed into a prime (18864668746921) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written in 19 ways as a sum of consecutive naturals, for example, 81146016 + ... + 81378161.

Almost surely, 2^{18864668796921} is an apocalyptic number.

It is an amenable number.

18864668796921 is a deficient number, since it is larger than the sum of its proper divisors (9335551424571).

18864668796921 is a wasteful number, since it uses less digits than its factorization.

18864668796921 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 162525622 (or 162525613 counting only the distinct ones).

The product of its digits is 3009871872, while the sum is 81.

The spelling of 18864668796921 in words is "eighteen trillion, eight hundred sixty-four billion, six hundred sixty-eight million, seven hundred ninety-six thousand, nine hundred twenty-one".