315921 has 16 divisors (see below), whose sum is σ = 450560. Its totient is φ = 196560.

The previous prime is 315907. The next prime is 315937. The reversal of 315921 is 129513.

It is not a de Polignac number, because 315921 - 2⁶ = 315857 is a prime.

It is an Ulam number.

It is a Duffinian number.

It is a Curzon number.

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 315921.

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

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 15 ways as a sum of consecutive naturals, for example, 3960 + ... + 4038.

It is an arithmetic number, because the mean of its divisors is an integer number (28160).

2³¹⁵⁹²¹ is an apocalyptic number.

315921 is a gapful number since it is divisible by the number (31) formed by its first and last digit.

It is an amenable number.

315921 is a deficient number, since it is larger than the sum of its proper divisors (134639).

315921 is a wasteful number, since it uses less digits than its factorization.

315921 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 156.

The product of its digits is 270, while the sum is 21.

The square root of 315921 is about 562.0685011633. The cubic root of 315921 is about 68.1071695333.

The spelling of 315921 in words is "three hundred fifteen thousand, nine hundred twenty-one".