21531552044 has 6 divisors (see below), whose sum is σ = 37680216084. Its totient is φ = 10765776020.

The previous prime is 21531552041. The next prime is 21531552061. The reversal of 21531552044 is 44025513512.

It is a self number, because there is not a number n which added to its sum of digits gives 21531552044.

It is not an unprimeable number, because it can be changed into a prime (21531552041) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 2691444002 + ... + 2691444009.

It is an arithmetic number, because the mean of its divisors is an integer number (6280036014).

Almost surely, 2^21531552044 is an apocalyptic number.

It is an amenable number.

21531552044 is a deficient number, since it is larger than the sum of its proper divisors (16148664040).

21531552044 is a wasteful number, since it uses less digits than its factorization.

21531552044 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5382888015 (or 5382888013 counting only the distinct ones).

The product of its (nonzero) digits is 24000, while the sum is 32.

The spelling of 21531552044 in words is "twenty-one billion, five hundred thirty-one million, five hundred fifty-two thousand, forty-four".