18579691021 has 4 divisors (see below), whose sum is σ = 18618480000. Its totient is φ = 18540902044.

The previous prime is 18579690989. The next prime is 18579691033. The reversal of 18579691021 is 12019697581.

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.

It is a cyclic number.

It is not a de Polignac number, because 18579691021 - 2⁵ = 18579690989 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (18579691061) 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, 19393771 + ... + 19394728.

It is an arithmetic number, because the mean of its divisors is an integer number (4654620000).

Almost surely, 2^18579691021 is an apocalyptic number.

It is an amenable number.

18579691021 is a deficient number, since it is larger than the sum of its proper divisors (38788979).

18579691021 is an equidigital number, since it uses as much as digits as its factorization.

18579691021 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 38788978.

The product of its (nonzero) digits is 272160, while the sum is 49.

The spelling of 18579691021 in words is "eighteen billion, five hundred seventy-nine million, six hundred ninety-one thousand, twenty-one".