21924795921 has 16 divisors (see below), whose sum is σ = 33413768064. Its totient is φ = 12526746624.

The previous prime is 21924795917. The next prime is 21924795929. The reversal of 21924795921 is 12959742912.

It is not a de Polignac number, because 21924795921 - 2² = 21924795917 is a prime.

It is not an unprimeable number, because it can be changed into a prime (21924795929) 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, 95601 + ... + 230193.

It is an arithmetic number, because the mean of its divisors is an integer number (2088360504).

Almost surely, 2^21924795921 is an apocalyptic number.

21924795921 is a gapful number since it is divisible by the number (21) formed by its first and last digit.

It is an amenable number.

21924795921 is a deficient number, since it is larger than the sum of its proper divisors (11488972143).

21924795921 is a wasteful number, since it uses less digits than its factorization.

21924795921 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 142360.

The product of its digits is 816480, while the sum is 51.

The spelling of 21924795921 in words is "twenty-one billion, nine hundred twenty-four million, seven hundred ninety-five thousand, nine hundred twenty-one".