18123116721 has 8 divisors (see below), whose sum is σ = 24226275840. Its totient is φ = 12051017712.

The previous prime is 18123116681. The next prime is 18123116773. The reversal of 18123116721 is 12761132181.

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 18123116721 - 2¹⁰ = 18123115697 is a prime.

It is not an unprimeable number, because it can be changed into a prime (18123116521) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 7763665 + ... + 7765998.

It is an arithmetic number, because the mean of its divisors is an integer number (3028284480).

Almost surely, 2^18123116721 is an apocalyptic number.

It is an amenable number.

18123116721 is a deficient number, since it is larger than the sum of its proper divisors (6103159119).

18123116721 is a wasteful number, since it uses less digits than its factorization.

18123116721 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 15530055.

The product of its digits is 4032, while the sum is 33.

The spelling of 18123116721 in words is "eighteen billion, one hundred twenty-three million, one hundred sixteen thousand, seven hundred twenty-one".