18456761721 has 16 divisors (see below), whose sum is σ = 24768880640. Its totient is φ = 12224630160.

The previous prime is 18456761707. The next prime is 18456761737. The reversal of 18456761721 is 12716765481.

It is not a de Polignac number, because 18456761721 - 2⁶ = 18456761657 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (18456761221) 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, 1911576 + ... + 1921206.

It is an arithmetic number, because the mean of its divisors is an integer number (1548055040).

Almost surely, 2^18456761721 is an apocalyptic number.

It is an amenable number.

18456761721 is a deficient number, since it is larger than the sum of its proper divisors (6312118919).

18456761721 is a wasteful number, since it uses less digits than its factorization.

18456761721 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 13716.

The product of its digits is 564480, while the sum is 48.

The spelling of 18456761721 in words is "eighteen billion, four hundred fifty-six million, seven hundred sixty-one thousand, seven hundred twenty-one".