1311857881 has 4 divisors (see below), whose sum is σ = 1312202212. Its totient is φ = 1311513552.

The previous prime is 1311857879. The next prime is 1311857909. The reversal of 1311857881 is 1887581131.

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

It can be written as a sum of positive squares in 2 ways, for example, as 1285939600 + 25918281 = 35860^2 + 5091^2 .

It is a cyclic number.

It is not a de Polignac number, because 1311857881 - 2¹ = 1311857879 is a prime.

It is a super-2 number, since 2×1311857881² = 3441942199883620322, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (1311857801) 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, 166386 + ... + 174091.

It is an arithmetic number, because the mean of its divisors is an integer number (328050553).

Almost surely, 2^1311857881 is an apocalyptic number.

It is an amenable number.

1311857881 is a deficient number, since it is larger than the sum of its proper divisors (344331).

1311857881 is an equidigital number, since it uses as much as digits as its factorization.

1311857881 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 344330.

The product of its digits is 53760, while the sum is 43.

The square root of 1311857881 is about 36219.5786971632. The cubic root of 1311857881 is about 1094.7012052146.

The spelling of 1311857881 in words is "one billion, three hundred eleven million, eight hundred fifty-seven thousand, eight hundred eighty-one".