21252313 has 4 divisors (see below), whose sum is σ = 21261568. Its totient is φ = 21243060.

The previous prime is 21252293. The next prime is 21252323. The reversal of 21252313 is 31325212.

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, 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 21252313 - 2⁵ = 21252281 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21252323) 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, 1720 + ... + 6742.

It is an arithmetic number, because the mean of its divisors is an integer number (5315392).

Almost surely, 2^21252313 is an apocalyptic number.

It is an amenable number.

21252313 is a deficient number, since it is larger than the sum of its proper divisors (9255).

21252313 is an equidigital number, since it uses as much as digits as its factorization.

21252313 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 9254.

The product of its digits is 360, while the sum is 19.

The square root of 21252313 is about 4610.0231018944. The cubic root of 21252313 is about 276.9929620649.

Adding to 21252313 its reverse (31325212), we get a palindrome (52577525).

It can be divided in two parts, 212 and 52313, that added together give a palindrome (52525).

The spelling of 21252313 in words is "twenty-one million, two hundred fifty-two thousand, three hundred thirteen".