21164413 has 4 divisors (see below), whose sum is σ = 21847168. Its totient is φ = 20481660.

The previous prime is 21164401. The next prime is 21164431. The reversal of 21164413 is 31446112.

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 a de Polignac number, because none of the positive numbers 2^k-21164413 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 (21164453) 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, 341331 + ... + 341392.

It is an arithmetic number, because the mean of its divisors is an integer number (5461792).

Almost surely, 2^21164413 is an apocalyptic number.

It is an amenable number.

21164413 is a deficient number, since it is larger than the sum of its proper divisors (682755).

21164413 is an equidigital number, since it uses as much as digits as its factorization.

21164413 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 682754.

The product of its digits is 576, while the sum is 22.

The square root of 21164413 is about 4600.4796489062. The cubic root of 21164413 is about 276.6105515133.

The spelling of 21164413 in words is "twenty-one million, one hundred sixty-four thousand, four hundred thirteen".