1231320313 has 4 divisors (see below), whose sum is σ = 1231426548. Its totient is φ = 1231214080.

The previous prime is 1231320281. The next prime is 1231320317. The reversal of 1231320313 is 3130231321.

1231320313 = 24812² + 24813².

It is a semiprime because it is the product of two primes, and also a brilliant number, because the two primes have the same length.

It can be written as a sum of positive squares in 2 ways, for example, as 615684969 + 615635344 = 24813^2 + 24812^2 .

It is a cyclic number.

It is not a de Polignac number, because 1231320313 - 2⁵ = 1231320281 is a prime.

It is a super-2 number, since 2×1231320313² = 3032299426412835938, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (1231320317) 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, 33256 + ... + 59737.

It is an arithmetic number, because the mean of its divisors is an integer number (307856637).

Almost surely, 2^1231320313 is an apocalyptic number.

1231320313 is the 24813-rd centered square number.

It is an amenable number.

1231320313 is a deficient number, since it is larger than the sum of its proper divisors (106235).

1231320313 is an equidigital number, since it uses as much as digits as its factorization.

1231320313 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 106234.

The product of its (nonzero) digits is 324, while the sum is 19.

The square root of 1231320313 is about 35090.1740235069. The cubic root of 1231320313 is about 1071.8245032868.

Adding to 1231320313 its reverse (3130231321), we get a palindrome (4361551634).

The spelling of 1231320313 in words is "one billion, two hundred thirty-one million, three hundred twenty thousand, three hundred thirteen".