21879544 has 16 divisors (see below), whose sum is σ = 43437600. Its totient is φ = 10296192.

The previous prime is 21879523. The next prime is 21879551. The reversal of 21879544 is 44597812.

It is a junction number, because it is equal to n+sod(n) for n = 21879497 and 21879506.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 80304 + ... + 80575.

It is an arithmetic number, because the mean of its divisors is an integer number (2714850).

Almost surely, 2^21879544 is an apocalyptic number.

It is an amenable number.

21879544 is a deficient number, since it is larger than the sum of its proper divisors (21558056).

21879544 is a wasteful number, since it uses less digits than its factorization.

21879544 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 160902 (or 160898 counting only the distinct ones).

The product of its digits is 80640, while the sum is 40.

The square root of 21879544 is about 4677.5574822764. The cubic root of 21879544 is about 279.6915992179.

The spelling of 21879544 in words is "twenty-one million, eight hundred seventy-nine thousand, five hundred forty-four".