21839513 has 4 divisors (see below), whose sum is σ = 21954048. Its totient is φ = 21724980.

The previous prime is 21839507. The next prime is 21839557. The reversal of 21839513 is 31593812.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 21839513 - 2⁴ = 21839497 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 21839513.

It is not an unprimeable number, because it can be changed into a prime (21839563) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 56981 + ... + 57362.

It is an arithmetic number, because the mean of its divisors is an integer number (5488512).

Almost surely, 2^21839513 is an apocalyptic number.

It is an amenable number.

21839513 is a deficient number, since it is larger than the sum of its proper divisors (114535).

21839513 is a wasteful number, since it uses less digits than its factorization.

21839513 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 114534.

The product of its digits is 6480, while the sum is 32.

The square root of 21839513 is about 4673.2764737387. The cubic root of 21839513 is about 279.5209197062.

The spelling of 21839513 in words is "twenty-one million, eight hundred thirty-nine thousand, five hundred thirteen".