315722721 has 4 divisors (see below), whose sum is σ = 420963632. Its totient is φ = 210481812.

The previous prime is 315722683. The next prime is 315722741. The reversal of 315722721 is 127227513.

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 not a de Polignac number, because 315722721 - 2⁷ = 315722593 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (315722741) 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, 52620451 + ... + 52620456.

It is an arithmetic number, because the mean of its divisors is an integer number (105240908).

Almost surely, 2^315722721 is an apocalyptic number.

It is an amenable number.

315722721 is a deficient number, since it is larger than the sum of its proper divisors (105240911).

315722721 is a wasteful number, since it uses less digits than its factorization.

315722721 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 105240910.

The product of its digits is 5880, while the sum is 30.

The square root of 315722721 is about 17768.5880418226. The cubic root of 315722721 is about 680.9291802989.

It can be divided in two parts, 3157 and 22721, that added together give a triangular number (25878 = T₂₂₇).

The spelling of 315722721 in words is "three hundred fifteen million, seven hundred twenty-two thousand, seven hundred twenty-one".