315733721 has 4 divisors (see below), whose sum is σ = 321085200. Its totient is φ = 310382244.

The previous prime is 315733637. The next prime is 315733723. The reversal of 315733721 is 127337513.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a de Polignac number, because none of the positive numbers 2^k-315733721 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (315733723) 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, 2675651 + ... + 2675768.

It is an arithmetic number, because the mean of its divisors is an integer number (80271300).

Almost surely, 2^315733721 is an apocalyptic number.

It is an amenable number.

315733721 is a deficient number, since it is larger than the sum of its proper divisors (5351479).

315733721 is an equidigital number, since it uses as much as digits as its factorization.

315733721 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5351478.

The product of its digits is 13230, while the sum is 32.

The square root of 315733721 is about 17768.8975741322. The cubic root of 315733721 is about 680.9370882231.

The spelling of 315733721 in words is "three hundred fifteen million, seven hundred thirty-three thousand, seven hundred twenty-one".