21881884 has 24 divisors (see below), whose sum is σ = 39352320. Its totient is φ = 10641456.

The previous prime is 21881857. The next prime is 21881891. The reversal of 21881884 is 48818812.

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, 44689 + ... + 45175.

It is an arithmetic number, because the mean of its divisors is an integer number (1639680).

Almost surely, 2^21881884 is an apocalyptic number.

It is an amenable number.

21881884 is a deficient number, since it is larger than the sum of its proper divisors (17470436).

21881884 is a wasteful number, since it uses less digits than its factorization.

21881884 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 777 (or 775 counting only the distinct ones).

The product of its digits is 32768, while the sum is 40.

The square root of 21881884 is about 4677.8076061335. The cubic root of 21881884 is about 279.7015697946.

The spelling of 21881884 in words is "twenty-one million, eight hundred eighty-one thousand, eight hundred eighty-four".