1311115511 has 4 divisors (see below), whose sum is σ = 1315748712. Its totient is φ = 1306482312.

The previous prime is 1311115493. The next prime is 1311115567. The reversal of 1311115511 is 1155111131.

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 1311115511 - 2¹⁰ = 1311114487 is a prime.

It is a super-2 number, since 2×1311115511² = 3438047766369582242, which contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1311115571) 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, 2316176 + ... + 2316741.

It is an arithmetic number, because the mean of its divisors is an integer number (328937178).

Almost surely, 2^1311115511 is an apocalyptic number.

1311115511 is a deficient number, since it is larger than the sum of its proper divisors (4633201).

1311115511 is an equidigital number, since it uses as much as digits as its factorization.

1311115511 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4633200.

The product of its digits is 75, while the sum is 20.

The square root of 1311115511 is about 36209.3290603402. The cubic root of 1311115511 is about 1094.4946719997.

Adding to 1311115511 its reverse (1155111131), we get a palindrome (2466226642).

The spelling of 1311115511 in words is "one billion, three hundred eleven million, one hundred fifteen thousand, five hundred eleven".