311388 has 48 divisors (see below), whose sum is σ = 908544. Its totient is φ = 80640.

The previous prime is 311371. The next prime is 311393. The reversal of 311388 is 883113.

311388 is digitally balanced in base 3, because in such base it contains all the possibile digits an equal number of times.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (7) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 756 + ... + 1092.

It is an arithmetic number, because the mean of its divisors is an integer number (18928).

2³¹¹³⁸⁸ is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 311388, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (454272).

311388 is an abundant number, since it is smaller than the sum of its proper divisors (597156).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

311388 is a wasteful number, since it uses less digits than its factorization.

311388 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 362 (or 360 counting only the distinct ones).

The product of its digits is 576, while the sum is 24.

The square root of 311388 is about 558.0215049620. The cubic root of 311388 is about 67.7798532216.

Subtracting from 311388 its sum of digits (24), we obtain a square (311364 = 558²).

The spelling of 311388 in words is "three hundred eleven thousand, three hundred eighty-eight".