21320244313 has 4 divisors (see below), whose sum is σ = 21320692900. Its totient is φ = 21319795728.

The previous prime is 21320244263. The next prime is 21320244317. The reversal of 21320244313 is 31344202312.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 10603232784 + 10717011529 = 102972^2 + 103523^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21320244313 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21320244317) 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, 143238 + ... + 251311.

It is an arithmetic number, because the mean of its divisors is an integer number (5330173225).

Almost surely, 2^21320244313 is an apocalyptic number.

It is an amenable number.

21320244313 is a deficient number, since it is larger than the sum of its proper divisors (448587).

21320244313 is an equidigital number, since it uses as much as digits as its factorization.

21320244313 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 448586.

The product of its (nonzero) digits is 3456, while the sum is 25.

Adding to 21320244313 its reverse (31344202312), we get a palindrome (52664446625).

The spelling of 21320244313 in words is "twenty-one billion, three hundred twenty million, two hundred forty-four thousand, three hundred thirteen".