1311431081 has 2 divisors, whose sum is σ = 1311431082. Its totient is φ = 1311431080.

The previous prime is 1311431041. The next prime is 1311431087. The reversal of 1311431081 is 1801341131.

It is a happy number.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 1306099600 + 5331481 = 36140^2 + 2309^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-1311431081 is a prime.

It is a super-2 number, since 2×1311431081² = 3439702960425657122, which contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (1311431087) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 655715540 + 655715541.

It is an arithmetic number, because the mean of its divisors is an integer number (655715541).

Almost surely, 2^1311431081 is an apocalyptic number.

It is an amenable number.

1311431081 is a deficient number, since it is larger than the sum of its proper divisors (1).

1311431081 is an equidigital number, since it uses as much as digits as its factorization.

1311431081 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 288, while the sum is 23.

The square root of 1311431081 is about 36213.6863768382. The cubic root of 1311431081 is about 1094.5824755975.

The spelling of 1311431081 in words is "one billion, three hundred eleven million, four hundred thirty-one thousand, eighty-one".