21904323819 has 16 divisors (see below), whose sum is σ = 34528984320. Its totient is φ = 12085143840.

The previous prime is 21904323803. The next prime is 21904323871. The reversal of 21904323819 is 91832340912.

It is not a de Polignac number, because 21904323819 - 2⁴ = 21904323803 is a prime.

It is a super-2 number, since 2×21904323819² (a number of 21 digits) contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (21904323899) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 17983237 + ... + 17984454.

It is an arithmetic number, because the mean of its divisors is an integer number (2158061520).

Almost surely, 2^21904323819 is an apocalyptic number.

21904323819 is a gapful number since it is divisible by the number (29) formed by its first and last digit.

21904323819 is a deficient number, since it is larger than the sum of its proper divisors (12624660501).

21904323819 is a wasteful number, since it uses less digits than its factorization.

21904323819 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 35967730.

The product of its (nonzero) digits is 93312, while the sum is 42.

The spelling of 21904323819 in words is "twenty-one billion, nine hundred four million, three hundred twenty-three thousand, eight hundred nineteen".