311820 has 24 divisors (see below), whose sum is σ = 873264. Its totient is φ = 83136.

The previous prime is 311807. The next prime is 311821. The reversal of 311820 is 28113.

It is a happy number.

It is a Harshad number since it is a multiple of its sum of digits (15).

It is a self number, because there is not a number n which added to its sum of digits gives 311820.

It is not an unprimeable number, because it can be changed into a prime (311821) by changing a digit.

311820 is an untouchable number, because it is not equal to the sum of proper divisors of any number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 2539 + ... + 2658.

It is an arithmetic number, because the mean of its divisors is an integer number (36386).

2³¹¹⁸²⁰ is an apocalyptic number.

311820 is a gapful number since it is divisible by the number (30) formed by its first and last digit.

It is an amenable number.

311820 is an abundant number, since it is smaller than the sum of its proper divisors (561444).

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

311820 is a wasteful number, since it uses less digits than its factorization.

311820 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5209 (or 5207 counting only the distinct ones).

The product of its (nonzero) digits is 48, while the sum is 15.

The square root of 311820 is about 558.4084526581. The cubic root of 311820 is about 67.8111832303.

Adding to 311820 its reverse (28113), we get a palindrome (339933).

The spelling of 311820 in words is "three hundred eleven thousand, eight hundred twenty".