1311256657 has 8 divisors (see below), whose sum is σ = 1369938240. Its totient is φ = 1252714320.

The previous prime is 1311256649. The next prime is 1311256673. The reversal of 1311256657 is 7566521131.

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 1311256657 - 2³ = 1311256649 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (1311256607) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 15319 + ... + 53452.

It is an arithmetic number, because the mean of its divisors is an integer number (171242280).

Almost surely, 2^1311256657 is an apocalyptic number.

It is an amenable number.

1311256657 is a deficient number, since it is larger than the sum of its proper divisors (58681583).

1311256657 is an equidigital number, since it uses as much as digits as its factorization.

1311256657 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 69623.

The product of its digits is 37800, while the sum is 37.

The square root of 1311256657 is about 36211.2780359932. The cubic root of 1311256657 is about 1094.5339459361.

Adding to 1311256657 its reverse (7566521131), we get a palindrome (8877777788).

The spelling of 1311256657 in words is "one billion, three hundred eleven million, two hundred fifty-six thousand, six hundred fifty-seven".