21125236179 has 4 divisors (see below), whose sum is σ = 28166981576. Its totient is φ = 14083490784.

The previous prime is 21125236177. The next prime is 21125236189. The reversal of 21125236179 is 97163252112.

It is a semiprime because it is the product of two primes.

It is not a de Polignac number, because 21125236179 - 2¹ = 21125236177 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21125236177) 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, 3520872694 + ... + 3520872699.

It is an arithmetic number, because the mean of its divisors is an integer number (7041745394).

Almost surely, 2^21125236179 is an apocalyptic number.

21125236179 is a deficient number, since it is larger than the sum of its proper divisors (7041745397).

21125236179 is an equidigital number, since it uses as much as digits as its factorization.

21125236179 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 7041745396.

The product of its digits is 45360, while the sum is 39.

The spelling of 21125236179 in words is "twenty-one billion, one hundred twenty-five million, two hundred thirty-six thousand, one hundred seventy-nine".