18764675721 has 24 divisors (see below), whose sum is σ = 29580988320. Its totient is φ = 11367758400.

The previous prime is 18764675687. The next prime is 18764675731. The reversal of 18764675721 is 12757646781.

18764675721 is a `hidden beast` number, since 1 + 8 + 7 + 6 + 4 + 67 + 572 + 1 = 666.

It is not a de Polignac number, because 18764675721 - 2¹⁷ = 18764544649 is a prime.

It is a super-2 number, since 2×18764675721² (a number of 21 digits) contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (18764675731) 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, 204901 + ... + 281981.

It is an arithmetic number, because the mean of its divisors is an integer number (1232541180).

Almost surely, 2^18764675721 is an apocalyptic number.

18764675721 is a gapful number since it is divisible by the number (11) formed by its first and last digit.

It is an amenable number.

18764675721 is a deficient number, since it is larger than the sum of its proper divisors (10816312599).

18764675721 is a wasteful number, since it uses less digits than its factorization.

18764675721 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 79557 (or 79554 counting only the distinct ones).

The product of its digits is 3951360, while the sum is 54.

The spelling of 18764675721 in words is "eighteen billion, seven hundred sixty-four million, six hundred seventy-five thousand, seven hundred twenty-one".