21932813 has 4 divisors (see below), whose sum is σ = 25066080. Its totient is φ = 18799548.

The previous prime is 21932809. The next prime is 21932819. The reversal of 21932813 is 31823912.

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 21932813 - 2² = 21932809 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 (21932819) 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, 1566623 + ... + 1566636.

It is an arithmetic number, because the mean of its divisors is an integer number (6266520).

Almost surely, 2^21932813 is an apocalyptic number.

It is an amenable number.

21932813 is a deficient number, since it is larger than the sum of its proper divisors (3133267).

21932813 is an equidigital number, since it uses as much as digits as its factorization.

21932813 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3133266.

The product of its digits is 2592, while the sum is 29.

The square root of 21932813 is about 4683.2481249663. The cubic root of 21932813 is about 279.9183988401.

The spelling of 21932813 in words is "twenty-one million, nine hundred thirty-two thousand, eight hundred thirteen".