21873839 has 12 divisors (see below), whose sum is σ = 23817816. Its totient is φ = 20079072.

The previous prime is 21873833. The next prime is 21873853. The reversal of 21873839 is 93837812.

It is not a de Polignac number, because 21873839 - 2⁴ = 21873823 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 21873796 and 21873805.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21873833) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 58457 + ... + 58829.

It is an arithmetic number, because the mean of its divisors is an integer number (1984818).

Almost surely, 2^21873839 is an apocalyptic number.

21873839 is a deficient number, since it is larger than the sum of its proper divisors (1943977).

21873839 is a wasteful number, since it uses less digits than its factorization.

21873839 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 746 (or 733 counting only the distinct ones).

The product of its digits is 72576, while the sum is 41.

The square root of 21873839 is about 4676.9476156998. The cubic root of 21873839 is about 279.6672876314.

The spelling of 21873839 in words is "twenty-one million, eight hundred seventy-three thousand, eight hundred thirty-nine".