315861921 has 24 divisors (see below), whose sum is σ = 504092160. Its totient is φ = 189568896.

The previous prime is 315861913. The next prime is 315861941. The reversal of 315861921 is 129168513.

315861921 is a `hidden beast` number, since 3 + 15 + 8 + 619 + 21 = 666.

It is not a de Polignac number, because 315861921 - 2³ = 315861913 is a prime.

It is not an unprimeable number, because it can be changed into a prime (315861941) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 41361 + ... + 48398.

It is an arithmetic number, because the mean of its divisors is an integer number (21003840).

Almost surely, 2^315861921 is an apocalyptic number.

It is an amenable number.

315861921 is a deficient number, since it is larger than the sum of its proper divisors (188230239).

315861921 is a wasteful number, since it uses less digits than its factorization.

315861921 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 89805 (or 89802 counting only the distinct ones).

The product of its digits is 12960, while the sum is 36.

The square root of 315861921 is about 17772.5046349692. The cubic root of 315861921 is about 681.0292379433.

The spelling of 315861921 in words is "three hundred fifteen million, eight hundred sixty-one thousand, nine hundred twenty-one".