311389 has 8 divisors (see below), whose sum is σ = 355320. Its totient is φ = 270336.

The previous prime is 311371. The next prime is 311393. The reversal of 311389 is 983113.

It can be written as a sum of positive squares in 4 ways, for example, as 25 + 311364 = 5^2 + 558^2 .

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

It is a 7-Lehmer number, since φ(311389) divides (311389-1)⁷.

It is a cyclic number.

It is not a de Polignac number, because 311389 - 2¹⁷ = 180317 is a prime.

It is an Ulam number.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (311329) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 484 + ... + 925.

It is an arithmetic number, because the mean of its divisors is an integer number (44415).

2³¹¹³⁸⁹ is an apocalyptic number.

It is an amenable number.

311389 is a deficient number, since it is larger than the sum of its proper divisors (43931).

311389 is a wasteful number, since it uses less digits than its factorization.

311389 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1439.

The product of its digits is 648, while the sum is 25.

The square root of 311389 is about 558.0224009840. The cubic root of 311389 is about 67.7799257782.

Subtracting from 311389 its sum of digits (25), we obtain a square (311364 = 558²).

The spelling of 311389 in words is "three hundred eleven thousand, three hundred eighty-nine".