18386721951 has 16 divisors (see below), whose sum is σ = 26406403296. Its totient is φ = 11312781696.

The previous prime is 18386721929. The next prime is 18386722001. The reversal of 18386721951 is 15912768381.

It is not a de Polignac number, because 18386721951 - 2⁶ = 18386721887 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 18386721894 and 18386721903.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (18386721911) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 180621 + ... + 263433.

It is an arithmetic number, because the mean of its divisors is an integer number (1650400206).

Almost surely, 2^18386721951 is an apocalyptic number.

18386721951 is a deficient number, since it is larger than the sum of its proper divisors (8019681345).

18386721951 is a wasteful number, since it uses less digits than its factorization.

18386721951 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 88522.

The product of its digits is 725760, while the sum is 51.

The spelling of 18386721951 in words is "eighteen billion, three hundred eighty-six million, seven hundred twenty-one thousand, nine hundred fifty-one".