21896839 has 4 divisors (see below), whose sum is σ = 21908920. Its totient is φ = 21884760.

The previous prime is 21896803. The next prime is 21896843. The reversal of 21896839 is 93869812.

It is a semiprime because it is the product of two primes, and also a brilliant number, because the two primes have the same length.

It is a cyclic number.

It is not a de Polignac number, because 21896839 - 2¹⁹ = 21372551 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21896879) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 2709 + ... + 7150.

It is an arithmetic number, because the mean of its divisors is an integer number (5477230).

Almost surely, 2^21896839 is an apocalyptic number.

21896839 is a deficient number, since it is larger than the sum of its proper divisors (12081).

21896839 is an equidigital number, since it uses as much as digits as its factorization.

21896839 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 12080.

The product of its digits is 186624, while the sum is 46.

The square root of 21896839 is about 4679.4058383517. The cubic root of 21896839 is about 279.7652752233.

The spelling of 21896839 in words is "twenty-one million, eight hundred ninety-six thousand, eight hundred thirty-nine".