• 312 can be written using four 4's:

See also 113.

---

312 has 16 divisors (see below), whose sum is σ = 840. Its totient is φ = 96.

The previous prime is 311. The next prime is 313. The reversal of 312 is 213.

312 is nontrivially palindromic in base 5.

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

It is an interprime number because it is at equal distance from previous prime (311) and next prime (313).

It is a Harshad number since it is a multiple of its sum of digits (6).

It is a nude number because it is divisible by every one of its digits and also a Zuckerman number because it is divisible by the product of its digits.

312 is an idoneal number.

It is one of the 548 Lynch-Bell numbers.

312 is a nontrivial repdigit in base 5.

It is a plaindrome in base 5, base 15 and base 16.

It is a nialpdrome in base 5 and base 12.

It is a zygodrome in base 5.

It is a self number, because there is not a number n which added to its sum of digits gives 312.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (311) 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, 18 + ... + 30.

2³¹² 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 312, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (420).

312 is an abundant number, since it is smaller than the sum of its proper divisors (528).

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

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

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

The sum of its prime factors is 22 (or 18 counting only the distinct ones).

The product of its digits is 6, while the sum is 6.

The square root of 312 is about 17.6635217327. The cubic root of 312 is about 6.7824228860.

Adding to 312 its reverse (213), we get a palindrome (525).

Subtracting from 312 its reverse (213), we obtain a palindrome (99).

It can be divided in two parts, 31 and 2, that added together give a palindrome (33).

The spelling of 312 in words is "three hundred twelve", and thus it is an aban number, an iban number, and an oban number.