312891 has 4 divisors (see below), whose sum is σ = 417192. Its totient is φ = 208592.

The previous prime is 312887. The next prime is 312899. The reversal of 312891 is 198213.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 198213 = 3 ⋅66071.

It is a cyclic number.

It is not a de Polignac number, because 312891 - 2² = 312887 is a prime.

It is a D-number.

It is an inconsummate number, since it does not exist a number n which divided by its sum of digits gives 312891.

It is not an unprimeable number, because it can be changed into a prime (312899) 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, 52146 + ... + 52151.

It is an arithmetic number, because the mean of its divisors is an integer number (104298).

2³¹²⁸⁹¹ is an apocalyptic number.

312891 is a deficient number, since it is larger than the sum of its proper divisors (104301).

312891 is a wasteful number, since it uses less digits than its factorization.

312891 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 104300.

The product of its digits is 432, while the sum is 24.

The square root of 312891 is about 559.3666060823. The cubic root of 312891 is about 67.8887309468. Note that the first 3 decimals are identical.

The spelling of 312891 in words is "three hundred twelve thousand, eight hundred ninety-one".