21904919431 has 4 divisors (see below), whose sum is σ = 21985749664. Its totient is φ = 21824089200.

The previous prime is 21904919401. The next prime is 21904919437. The reversal of 21904919431 is 13491940912.

It is a happy number.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 21904919431 - 2¹³ = 21904911239 is a prime.

It is a super-2 number, since 2×21904919431² (a number of 21 digits) contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21904919437) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 40414710 + ... + 40415251.

It is an arithmetic number, because the mean of its divisors is an integer number (5496437416).

Almost surely, 2^21904919431 is an apocalyptic number.

21904919431 is a deficient number, since it is larger than the sum of its proper divisors (80830233).

21904919431 is an equidigital number, since it uses as much as digits as its factorization.

21904919431 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 80830232.

The product of its (nonzero) digits is 69984, while the sum is 43.

The spelling of 21904919431 in words is "twenty-one billion, nine hundred four million, nine hundred nineteen thousand, four hundred thirty-one".