21391589079 has 32 divisors (see below), whose sum is σ = 36313251840. Its totient is φ = 12191808096.

The previous prime is 21391589069. The next prime is 21391589101. The reversal of 21391589079 is 97098519312.

21391589079 is a `hidden beast` number, since 21 + 39 + 1 + 589 + 0 + 7 + 9 = 666.

It is not a de Polignac number, because 21391589079 - 2⁷ = 21391588951 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21391589069) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 75372 + ... + 220145.

It is an arithmetic number, because the mean of its divisors is an integer number (1134789120).

Almost surely, 2^21391589079 is an apocalyptic number.

21391589079 is a deficient number, since it is larger than the sum of its proper divisors (14921662761).

21391589079 is a wasteful number, since it uses less digits than its factorization.

21391589079 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 295916 (or 295910 counting only the distinct ones).

The product of its (nonzero) digits is 1224720, while the sum is 54.

The spelling of 21391589079 in words is "twenty-one billion, three hundred ninety-one million, five hundred eighty-nine thousand, seventy-nine".