311989 has 4 divisors (see below), whose sum is σ = 315180. Its totient is φ = 308800.

The previous prime is 311981. The next prime is 312007. The reversal of 311989 is 989113.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 989113 = 269 ⋅3677.

It can be written as a sum of positive squares in 2 ways, for example, as 293764 + 18225 = 542^2 + 135^2 .

It is a cyclic number.

It is not a de Polignac number, because 311989 - 2³ = 311981 is a prime.

It is a super-2 number, since 2×311989² = 194674272242, which contains 22 as substring.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 311989.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (311981) 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, 1444 + ... + 1645.

It is an arithmetic number, because the mean of its divisors is an integer number (78795).

2³¹¹⁹⁸⁹ is an apocalyptic number.

It is an amenable number.

311989 is a deficient number, since it is larger than the sum of its proper divisors (3191).

311989 is a wasteful number, since it uses less digits than its factorization.

311989 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3190.

The product of its digits is 1944, while the sum is 31.

The square root of 311989 is about 558.5597550844. The cubic root of 311989 is about 67.8234317713.

The spelling of 311989 in words is "three hundred eleven thousand, nine hundred eighty-nine".