21550500444 has 24 divisors (see below), whose sum is σ = 54855819648. Its totient is φ = 6530454640.

The previous prime is 21550500373. The next prime is 21550500479. The reversal of 21550500444 is 44400505512.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 81630552 + ... + 81630815.

It is an arithmetic number, because the mean of its divisors is an integer number (2285659152).

Almost surely, 2^21550500444 is an apocalyptic number.

It is an amenable number.

21550500444 is an abundant number, since it is smaller than the sum of its proper divisors (33305319204).

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

21550500444 is a wasteful number, since it uses less digits than its factorization.

21550500444 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 163261385 (or 163261383 counting only the distinct ones).

The product of its (nonzero) digits is 16000, while the sum is 30.

The spelling of 21550500444 in words is "twenty-one billion, five hundred fifty million, five hundred thousand, four hundred forty-four".