312640 has 28 divisors (see below), whose sum is σ = 745236. Its totient is φ = 124928.

The previous prime is 312623. The next prime is 312643. The reversal of 312640 is 46213.

312640 is nontrivially palindromic in base 3.

It can be written as a sum of positive squares in 2 ways, for example, as 215296 + 97344 = 464^2 + 312^2 .

It is a Harshad number since it is a multiple of its sum of digits (16).

It is an Ulam number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (312643) 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, 169 + ... + 808.

2³¹²⁶⁴⁰ is an apocalyptic number.

It is an amenable number.

312640 is an abundant number, since it is smaller than the sum of its proper divisors (432596).

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

312640 is an equidigital number, since it uses as much as digits as its factorization.

312640 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 994 (or 984 counting only the distinct ones).

The product of its (nonzero) digits is 144, while the sum is 16.

The square root of 312640 is about 559.1422001602. The cubic root of 312640 is about 67.8705727277.

Adding to 312640 its reverse (46213), we get a palindrome (358853).

The spelling of 312640 in words is "three hundred twelve thousand, six hundred forty".