21550553980 has 24 divisors (see below), whose sum is σ = 45375588720. Its totient is φ = 8597473920.

The previous prime is 21550553951. The next prime is 21550553987. The reversal of 21550553980 is 8935505512.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21550553987) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 1413961 + ... + 1429120.

It is an arithmetic number, because the mean of its divisors is an integer number (1890649530).

Almost surely, 2^21550553980 is an apocalyptic number.

21550553980 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21550553980 is an abundant number, since it is smaller than the sum of its proper divisors (23825034740).

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

21550553980 is a wasteful number, since it uses less digits than its factorization.

21550553980 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2843469 (or 2843467 counting only the distinct ones).

The product of its (nonzero) digits is 270000, while the sum is 43.

The spelling of 21550553980 in words is "twenty-one billion, five hundred fifty million, five hundred fifty-three thousand, nine hundred eighty".