311312021 has 4 divisors (see below), whose sum is σ = 312021600. Its totient is φ = 310602444.

The previous prime is 311311981. The next prime is 311312039. The reversal of 311312021 is 120213113.

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, and also an emirpimes, since its reverse is a distinct semiprime: 120213113 = 167 ⋅719839.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-311312021 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 311311987 and 311312005.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (311312051) 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, 354131 + ... + 355008.

It is an arithmetic number, because the mean of its divisors is an integer number (78005400).

Almost surely, 2^311312021 is an apocalyptic number.

It is an amenable number.

311312021 is a deficient number, since it is larger than the sum of its proper divisors (709579).

311312021 is an equidigital number, since it uses as much as digits as its factorization.

311312021 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 709578.

The product of its (nonzero) digits is 36, while the sum is 14.

The square root of 311312021 is about 17644.0364146076. The cubic root of 311312021 is about 677.7433998797.

Adding to 311312021 its reverse (120213113), we get a palindrome (431525134).

The spelling of 311312021 in words is "three hundred eleven million, three hundred twelve thousand, twenty-one".