1311531123 has 16 divisors (see below), whose sum is σ = 1999699200. Its totient is φ = 749005536.

The previous prime is 1311531103. The next prime is 1311531127. The reversal of 1311531123 is 3211351131.

It is not a de Polignac number, because 1311531123 - 2⁶ = 1311531059 is a prime.

It is a super-2 number, since 2×1311531123² = 3440227773195282258, which contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (21).

It is a self number, because there is not a number n which added to its sum of digits gives 1311531123.

It is not an unprimeable number, because it can be changed into a prime (1311531127) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 20053 + ... + 55001.

It is an arithmetic number, because the mean of its divisors is an integer number (124981200).

Almost surely, 2^1311531123 is an apocalyptic number.

1311531123 is a deficient number, since it is larger than the sum of its proper divisors (688168077).

1311531123 is a wasteful number, since it uses less digits than its factorization.

1311531123 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 36746.

The product of its digits is 270, while the sum is 21.

The square root of 1311531123 is about 36215.0676238496. The cubic root of 1311531123 is about 1094.6103081531.

Adding to 1311531123 its reverse (3211351131), we get a palindrome (4522882254).

The spelling of 1311531123 in words is "one billion, three hundred eleven million, five hundred thirty-one thousand, one hundred twenty-three".