311640 has 96 divisors (see below), whose sum is σ = 1108080. Its totient is φ = 69888.

The previous prime is 311609. The next prime is 311653. The reversal of 311640 is 46113.

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

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 23 ways as a sum of consecutive naturals, for example, 5854 + ... + 5906.

2³¹¹⁶⁴⁰ is an apocalyptic number.

311640 is a gapful number since it is divisible by the number (30) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 311640, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (554040).

311640 is an abundant number, since it is smaller than the sum of its proper divisors (796440).

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

311640 is a wasteful number, since it uses less digits than its factorization.

311640 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 81 (or 70 counting only the distinct ones).

The product of its (nonzero) digits is 72, while the sum is 15.

The square root of 311640 is about 558.2472570466. The cubic root of 311640 is about 67.7981325788.

Adding to 311640 its sum of digits (15), we get a triangular number (311655 = T₇₈₉).

Adding to 311640 its reverse (46113), we get a palindrome (357753).

The spelling of 311640 in words is "three hundred eleven thousand, six hundred forty".