21239113 has 4 divisors (see below), whose sum is σ = 24273280. Its totient is φ = 18204948.

The previous prime is 21239087. The next prime is 21239173. The reversal of 21239113 is 31193212.

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 21239113 - 2⁵ = 21239081 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21239173) 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, 1517073 + ... + 1517086.

It is an arithmetic number, because the mean of its divisors is an integer number (6068320).

Almost surely, 2^21239113 is an apocalyptic number.

It is an amenable number.

21239113 is a deficient number, since it is larger than the sum of its proper divisors (3034167).

21239113 is an equidigital number, since it uses as much as digits as its factorization.

21239113 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3034166.

The product of its digits is 324, while the sum is 22.

The square root of 21239113 is about 4608.5912164131. The cubic root of 21239113 is about 276.9356025931.

It can be divided in two parts, 2123 and 9113, that added together give a square (11236 = 106²).

The spelling of 21239113 in words is "twenty-one million, two hundred thirty-nine thousand, one hundred thirteen".