21655576320 has 144 divisors (see below), whose sum is σ = 79042951680. Its totient is φ = 4949839872.

The previous prime is 21655576303. The next prime is 21655576337. The reversal of 21655576320 is 2367555612.

It is an interprime number because it is at equal distance from previous prime (21655576303) and next prime (21655576337).

It is a Harshad number since it is a multiple of its sum of digits (42).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 375940 + ... + 429699.

Almost surely, 2^21655576320 is an apocalyptic number.

21655576320 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21655576320 is an abundant number, since it is smaller than the sum of its proper divisors (57387375360).

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

21655576320 is an equidigital number, since it uses as much as digits as its factorization.

21655576320 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 805670 (or 805656 counting only the distinct ones).

The product of its (nonzero) digits is 378000, while the sum is 42.

The spelling of 21655576320 in words is "twenty-one billion, six hundred fifty-five million, five hundred seventy-six thousand, three hundred twenty".