1118312581 has 4 divisors (see below), whose sum is σ = 1184095692. Its totient is φ = 1052529472.

The previous prime is 1118312579. The next prime is 1118312593. The reversal of 1118312581 is 1852138111.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 1852138111 = 83 ⋅22314917.

It can be written as a sum of positive squares in 2 ways, for example, as 867597025 + 250715556 = 29455^2 + 15834^2 .

It is a cyclic number.

It is not a de Polignac number, because 1118312581 - 2¹ = 1118312579 is a prime.

It is a super-2 number, since 2×1118312581² = 2501246057645763122, 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 (1118312521) 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, 32891530 + ... + 32891563.

It is an arithmetic number, because the mean of its divisors is an integer number (296023923).

Almost surely, 2^1118312581 is an apocalyptic number.

It is an amenable number.

1118312581 is a deficient number, since it is larger than the sum of its proper divisors (65783111).

1118312581 is an equidigital number, since it uses as much as digits as its factorization.

1118312581 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 65783110.

The product of its digits is 1920, while the sum is 31.

The square root of 1118312581 is about 33441.1809151531. The cubic root of 1118312581 is about 1037.9770157753.

The spelling of 1118312581 in words is "one billion, one hundred eighteen million, three hundred twelve thousand, five hundred eighty-one".