1313323721 has 2 divisors, whose sum is σ = 1313323722. Its totient is φ = 1313323720.

The previous prime is 1313323663. The next prime is 1313323727. The reversal of 1313323721 is 1273233131.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 1079845321 + 233478400 = 32861^2 + 15280^2 .

It is a cyclic number.

It is not a de Polignac number, because 1313323721 - 2³⁰ = 239581897 is a prime.

It is a super-2 number, since 2×1313323721² = 3449638392282571682, which contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (1313323727) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 656661860 + 656661861.

It is an arithmetic number, because the mean of its divisors is an integer number (656661861).

Almost surely, 2^1313323721 is an apocalyptic number.

It is an amenable number.

1313323721 is a deficient number, since it is larger than the sum of its proper divisors (1).

1313323721 is an equidigital number, since it uses as much as digits as its factorization.

1313323721 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 2268, while the sum is 26.

The square root of 1313323721 is about 36239.8085121873. The cubic root of 1313323721 is about 1095.1087848109.

Adding to 1313323721 its reverse (1273233131), we get a palindrome (2586556852).

The spelling of 1313323721 in words is "one billion, three hundred thirteen million, three hundred twenty-three thousand, seven hundred twenty-one".