21839537 has 8 divisors (see below), whose sum is σ = 22377600. Its totient is φ = 21304624.

The previous prime is 21839507. The next prime is 21839557. The reversal of 21839537 is 73593812.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 21839537 - 2⁶ = 21839473 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 21839537.

It is not an unprimeable number, because it can be changed into a prime (21839507) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 19139 + ... + 20247.

It is an arithmetic number, because the mean of its divisors is an integer number (2797200).

Almost surely, 2^21839537 is an apocalyptic number.

It is an amenable number.

21839537 is a deficient number, since it is larger than the sum of its proper divisors (538063).

21839537 is a wasteful number, since it uses less digits than its factorization.

21839537 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1575.

The product of its digits is 45360, while the sum is 38.

The square root of 21839537 is about 4673.2790415296. The cubic root of 21839537 is about 279.5210220971.

The spelling of 21839537 in words is "twenty-one million, eight hundred thirty-nine thousand, five hundred thirty-seven".