9315991 has 2 divisors, whose sum is σ = 9315992. Its totient is φ = 9315990.

The previous prime is 9315973. The next prime is 9316007. The reversal of 9315991 is 1995139.

9315991 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a strong prime.

It is an emirp because it is prime and its reverse (1995139) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 9315991 - 2⁵ = 9315959 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 9315991.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (9315191) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 4657995 + 4657996.

It is an arithmetic number, because the mean of its divisors is an integer number (4657996).

Almost surely, 2^9315991 is an apocalyptic number.

9315991 is a deficient number, since it is larger than the sum of its proper divisors (1).

9315991 is an equidigital number, since it uses as much as digits as its factorization.

9315991 is an evil number, because the sum of its binary digits is even.

The product of its digits is 10935, while the sum is 37.

The square root of 9315991 is about 3052.2108380648. The cubic root of 9315991 is about 210.4148338151.

The spelling of 9315991 in words is "nine million, three hundred fifteen thousand, nine hundred ninety-one".