21550520000 has 70 divisors (see below), whose sum is σ = 53438384868. Its totient is φ = 8620192000.

The previous prime is 21550519997. The next prime is 21550520011. The reversal of 21550520000 is 2505512.

It is a Harshad number since it is a multiple of its sum of digits (20).

It is an unprimeable number.

It is a polite number, since it can be written in 9 ways as a sum of consecutive naturals, for example, 229382 + ... + 309381.

Almost surely, 2^21550520000 is an apocalyptic number.

21550520000 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21550520000 is an abundant number, since it is smaller than the sum of its proper divisors (31887864868).

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

21550520000 is an frugal number, since it uses more digits than its factorization.

21550520000 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 538795 (or 538770 counting only the distinct ones).

The product of its (nonzero) digits is 500, while the sum is 20.

The spelling of 21550520000 in words is "twenty-one billion, five hundred fifty million, five hundred twenty thousand".