21931057989 has 16 divisors (see below), whose sum is σ = 33368578240. Its totient is φ = 14225550480.

The previous prime is 21931057943. The next prime is 21931057999. The reversal of 21931057989 is 98975013912.

It is not a de Polignac number, because 21931057989 - 2⁷ = 21931057861 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 (21931057999) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 10975507 + ... + 10977504.

It is an arithmetic number, because the mean of its divisors is an integer number (2085536140).

Almost surely, 2^21931057989 is an apocalyptic number.

It is an amenable number.

21931057989 is a deficient number, since it is larger than the sum of its proper divisors (11437520251).

21931057989 is a wasteful number, since it uses less digits than its factorization.

21931057989 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 21953057 (or 21953051 counting only the distinct ones).

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

The spelling of 21931057989 in words is "twenty-one billion, nine hundred thirty-one million, fifty-seven thousand, nine hundred eighty-nine".