21607256091 has 64 divisors (see below), whose sum is σ = 31882346496. Its totient is φ = 12972220800.

The previous prime is 21607256059. The next prime is 21607256101. The reversal of 21607256091 is 19065270612.

It is not a de Polignac number, because 21607256091 - 2⁵ = 21607256059 is a prime.

It is not an unprimeable number, because it can be changed into a prime (21607256051) by changing a digit.

It is a polite number, since it can be written in 63 ways as a sum of consecutive naturals, for example, 19804456 + ... + 19805546.

It is an arithmetic number, because the mean of its divisors is an integer number (498161664).

Almost surely, 2^21607256091 is an apocalyptic number.

21607256091 is a deficient number, since it is larger than the sum of its proper divisors (10275090405).

21607256091 is a wasteful number, since it uses less digits than its factorization.

21607256091 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1392.

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

The spelling of 21607256091 in words is "twenty-one billion, six hundred seven million, two hundred fifty-six thousand, ninety-one".