312991 has 8 divisors (see below), whose sum is σ = 364064. Its totient is φ = 263520.

The previous prime is 312989. The next prime is 313003. The reversal of 312991 is 199213.

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 312991 - 2¹ = 312989 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (312931) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 61 + ... + 793.

It is an arithmetic number, because the mean of its divisors is an integer number (45508).

2³¹²⁹⁹¹ is an apocalyptic number.

312991 is a deficient number, since it is larger than the sum of its proper divisors (51073).

312991 is an equidigital number, since it uses as much as digits as its factorization.

312991 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 801.

The product of its digits is 486, while the sum is 25.

The square root of 312991 is about 559.4559857576. The cubic root of 312991 is about 67.8959625919.

The spelling of 312991 in words is "three hundred twelve thousand, nine hundred ninety-one".