21579423551 has 6 divisors (see below), whose sum is σ = 25102594800. Its totient is φ = 18496648716.

The previous prime is 21579423539. The next prime is 21579423577. The reversal of 21579423551 is 15532497512.

It is not a de Polignac number, because 21579423551 - 2²⁶ = 21512314687 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 (21579423511) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 220198151 + ... + 220198248.

It is an arithmetic number, because the mean of its divisors is an integer number (4183765800).

Almost surely, 2^21579423551 is an apocalyptic number.

21579423551 is a deficient number, since it is larger than the sum of its proper divisors (3523171249).

21579423551 is an equidigital number, since it uses as much as digits as its factorization.

21579423551 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 440396413 (or 440396406 counting only the distinct ones).

The product of its digits is 378000, while the sum is 44.

The spelling of 21579423551 in words is "twenty-one billion, five hundred seventy-nine million, four hundred twenty-three thousand, five hundred fifty-one".