311431681 has 4 divisors (see below), whose sum is σ = 339743664. Its totient is φ = 283119700.

The previous prime is 311431649. The next prime is 311431693. The reversal of 311431681 is 186134113.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 311431681 - 2⁵ = 311431649 is a prime.

It is a super-2 number, since 2×311431681² = 193979383860971522, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (311431781) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (7) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 14155975 + ... + 14155996.

It is an arithmetic number, because the mean of its divisors is an integer number (84935916).

Almost surely, 2^311431681 is an apocalyptic number.

It is an amenable number.

311431681 is a deficient number, since it is larger than the sum of its proper divisors (28311983).

311431681 is a wasteful number, since it uses less digits than its factorization.

311431681 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 28311982.

The product of its digits is 1728, while the sum is 28.

The square root of 311431681 is about 17647.4270362566. The cubic root of 311431681 is about 677.8302242245.

Adding to 311431681 its reverse (186134113), we get a palindrome (497565794).

The spelling of 311431681 in words is "three hundred eleven million, four hundred thirty-one thousand, six hundred eighty-one".