1311515431 has 4 divisors (see below), whose sum is σ = 1346961832. Its totient is φ = 1276069032.

The previous prime is 1311515423. The next prime is 1311515449. The reversal of 1311515431 is 1345151131.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 1311515431 - 2³ = 1311515423 is a prime.

It is a super-2 number, since 2×1311515431² = 3440145451502231522, which contains 22 as substring.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 1311515396 and 1311515405.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1311513431) 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, 17723145 + ... + 17723218.

It is an arithmetic number, because the mean of its divisors is an integer number (336740458).

Almost surely, 2^1311515431 is an apocalyptic number.

1311515431 is a deficient number, since it is larger than the sum of its proper divisors (35446401).

1311515431 is an equidigital number, since it uses as much as digits as its factorization.

1311515431 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 35446400.

The product of its digits is 900, while the sum is 25.

The square root of 1311515431 is about 36214.8509730470. The cubic root of 1311515431 is about 1094.6059425957.

Adding to 1311515431 its reverse (1345151131), we get a palindrome (2656666562).

The spelling of 1311515431 in words is "one billion, three hundred eleven million, five hundred fifteen thousand, four hundred thirty-one".