21900672391 has 32 divisors (see below), whose sum is σ = 24324572160. Its totient is φ = 19592052096.

The previous prime is 21900672389. The next prime is 21900672397. The reversal of 21900672391 is 19327600912.

It is a cyclic number.

It is not a de Polignac number, because 21900672391 - 2¹ = 21900672389 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 (21900672397) 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, 37309200 + ... + 37309786.

It is an arithmetic number, because the mean of its divisors is an integer number (760142880).

Almost surely, 2^21900672391 is an apocalyptic number.

21900672391 is a deficient number, since it is larger than the sum of its proper divisors (2423899769).

21900672391 is a wasteful number, since it uses less digits than its factorization.

21900672391 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1143.

The product of its (nonzero) digits is 40824, while the sum is 40.

The spelling of 21900672391 in words is "twenty-one billion, nine hundred million, six hundred seventy-two thousand, three hundred ninety-one".