21247113 has 4 divisors (see below), whose sum is σ = 28329488. Its totient is φ = 14164740.

The previous prime is 21247103. The next prime is 21247133. The reversal of 21247113 is 31174212.

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 not a de Polignac number, because 21247113 - 2⁵ = 21247081 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 21247113.

It is not an unprimeable number, because it can be changed into a prime (21247103) 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, 3541183 + ... + 3541188.

It is an arithmetic number, because the mean of its divisors is an integer number (7082372).

Almost surely, 2^21247113 is an apocalyptic number.

It is an amenable number.

21247113 is a deficient number, since it is larger than the sum of its proper divisors (7082375).

21247113 is an equidigital number, since it uses as much as digits as its factorization.

21247113 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 7082374.

The product of its digits is 336, while the sum is 21.

The square root of 21247113 is about 4609.4590788942. The cubic root of 21247113 is about 276.9703687454.

The spelling of 21247113 in words is "twenty-one million, two hundred forty-seven thousand, one hundred thirteen".