21915176820 has 48 divisors (see below), whose sum is σ = 61484572800. Its totient is φ = 5832420736.

The previous prime is 21915176819. The next prime is 21915176839. The reversal of 21915176820 is 2867151912.

It is a congruent number.

It is an unprimeable number.

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, 332895 + ... + 393254.

It is an arithmetic number, because the mean of its divisors is an integer number (1280928600).

Almost surely, 2^21915176820 is an apocalyptic number.

21915176820 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21915176820 is an abundant number, since it is smaller than the sum of its proper divisors (39569395980).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

21915176820 is a wasteful number, since it uses less digits than its factorization.

21915176820 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 726664 (or 726662 counting only the distinct ones).

The product of its (nonzero) digits is 60480, while the sum is 42.

The spelling of 21915176820 in words is "twenty-one billion, nine hundred fifteen million, one hundred seventy-six thousand, eight hundred twenty".