9315721 has 2 divisors, whose sum is σ = 9315722. Its totient is φ = 9315720.

The previous prime is 9315707. The next prime is 9315731. The reversal of 9315721 is 1275139.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 8732025 + 583696 = 2955^2 + 764^2 .

It is a cyclic number.

It is not a de Polignac number, because 9315721 - 2⁵ = 9315689 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 9315721.

It is not a weakly prime, because it can be changed into another prime (9315701) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 4657860 + 4657861.

It is an arithmetic number, because the mean of its divisors is an integer number (4657861).

Almost surely, 2^9315721 is an apocalyptic number.

It is an amenable number.

9315721 is a deficient number, since it is larger than the sum of its proper divisors (1).

9315721 is an equidigital number, since it uses as much as digits as its factorization.

9315721 is an evil number, because the sum of its binary digits is even.

The product of its digits is 1890, while the sum is 28.

The square root of 9315721 is about 3052.1666075101. The cubic root of 9315721 is about 210.4128010182.

The spelling of 9315721 in words is "nine million, three hundred fifteen thousand, seven hundred twenty-one".