9615991 has 12 divisors (see below), whose sum is σ = 12080656. Its totient is φ = 7492320.

The previous prime is 9615989. The next prime is 9616003. The reversal of 9615991 is 1995169.

It is not a de Polignac number, because 9615991 - 2¹ = 9615989 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (9615911) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 4830 + ... + 6523.

Almost surely, 2^9615991 is an apocalyptic number.

9615991 is a deficient number, since it is larger than the sum of its proper divisors (2464665).

9615991 is a wasteful number, since it uses less digits than its factorization.

9615991 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 11382 (or 11371 counting only the distinct ones).

The product of its digits is 21870, while the sum is 40.

The square root of 9615991 is about 3100.9661397700. The cubic root of 9615991 is about 212.6496551328.

The spelling of 9615991 in words is "nine million, six hundred fifteen thousand, nine hundred ninety-one".