21839572 has 12 divisors (see below), whose sum is σ = 38363220. Its totient is φ = 10878656.

The previous prime is 21839563. The next prime is 21839591. The reversal of 21839572 is 27593812.

It can be written as a sum of positive squares in 2 ways, for example, as 5225796 + 16613776 = 2286^2 + 4076^2 .

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, 9073 + ... + 11224.

It is an arithmetic number, because the mean of its divisors is an integer number (3196935).

Almost surely, 2^21839572 is an apocalyptic number.

It is an amenable number.

21839572 is a deficient number, since it is larger than the sum of its proper divisors (16523648).

21839572 is a wasteful number, since it uses less digits than its factorization.

21839572 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 20570 (or 20568 counting only the distinct ones).

The product of its digits is 30240, while the sum is 37.

The square root of 21839572 is about 4673.2827862221. The cubic root of 21839572 is about 279.5211714169.

The spelling of 21839572 in words is "twenty-one million, eight hundred thirty-nine thousand, five hundred seventy-two".