18330288721 has 4 divisors (see below), whose sum is σ = 18720294912. Its totient is φ = 17940282532.

The previous prime is 18330288673. The next prime is 18330288731. The reversal of 18330288721 is 12788203381.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4, and also an emirpimes, since its reverse is a distinct semiprime: 12788203381 = 433 ⋅29533957.

It is a cyclic number.

It is not a de Polignac number, because 18330288721 - 2¹⁵ = 18330255953 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (18330288731) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 195003025 + ... + 195003118.

It is an arithmetic number, because the mean of its divisors is an integer number (4680073728).

Almost surely, 2^18330288721 is an apocalyptic number.

It is an amenable number.

18330288721 is a deficient number, since it is larger than the sum of its proper divisors (390006191).

18330288721 is an equidigital number, since it uses as much as digits as its factorization.

18330288721 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 390006190.

The product of its (nonzero) digits is 129024, while the sum is 43.

The spelling of 18330288721 in words is "eighteen billion, three hundred thirty million, two hundred eighty-eight thousand, seven hundred twenty-one".