21579318139 has 4 divisors (see below), whose sum is σ = 21704054256. Its totient is φ = 21454582024.

The previous prime is 21579318073. The next prime is 21579318143. The reversal of 21579318139 is 93181397512.

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

It is a cyclic number.

It is not a de Polignac number, because 21579318139 - 2⁷ = 21579318011 is a prime.

It is a Smith number, since the sum of its digits (49) coincides with the sum of the digits of its prime factors. Since it is squarefree, it is also a hoax number.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 21579318092 and 21579318101.

It is not an unprimeable number, because it can be changed into a prime (21579418139) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 62367799 + ... + 62368144.

It is an arithmetic number, because the mean of its divisors is an integer number (5426013564).

Almost surely, 2^21579318139 is an apocalyptic number.

21579318139 is a deficient number, since it is larger than the sum of its proper divisors (124736117).

21579318139 is a wasteful number, since it uses less digits than its factorization.

21579318139 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 124736116.

The product of its digits is 408240, while the sum is 49.

The spelling of 21579318139 in words is "twenty-one billion, five hundred seventy-nine million, three hundred eighteen thousand, one hundred thirty-nine".