315981 has 20 divisors (see below), whose sum is σ = 487872. Its totient is φ = 203688.

The previous prime is 315977. The next prime is 316003. The reversal of 315981 is 189513.

It is not a de Polignac number, because 315981 - 2² = 315977 is a prime.

It is a super-2 number, since 2×315981² = 199687984722, which contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (27).

315981 is a lucky number.

It is a nialpdrome in base 14.

It is a congruent number.

It is an inconsummate number, since it does not exist a number n which divided by its sum of digits gives 315981.

It is not an unprimeable number, because it can be changed into a prime (315961) by changing a digit.

It is a polite number, since it can be written in 19 ways as a sum of consecutive naturals, for example, 3766 + ... + 3848.

2³¹⁵⁹⁸¹ is an apocalyptic number.

It is an amenable number.

315981 is a deficient number, since it is larger than the sum of its proper divisors (171891).

315981 is an equidigital number, since it uses as much as digits as its factorization.

315981 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 142 (or 133 counting only the distinct ones).

The product of its digits is 1080, while the sum is 27.

The square root of 315981 is about 562.1218729066. The cubic root of 315981 is about 68.1114809186. Note that the first 3 decimals are identical.

It can be divided in two parts, 3159 and 81, that added together give a triangular number (3240 = T₈₀).

The spelling of 315981 in words is "three hundred fifteen thousand, nine hundred eighty-one".