9921915 has 24 divisors (see below), whose sum is σ = 17793360. Its totient is φ = 5108544.

The previous prime is 9921907. The next prime is 9921917. The reversal of 9921915 is 5191299.

It is not a de Polignac number, because 9921915 - 2³ = 9921907 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 9921915.

It is not an unprimeable number, because it can be changed into a prime (9921917) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 2497 + ... + 5106.

It is an arithmetic number, because the mean of its divisors is an integer number (741390).

Almost surely, 2^9921915 is an apocalyptic number.

9921915 is a deficient number, since it is larger than the sum of its proper divisors (7871445).

9921915 is a wasteful number, since it uses less digits than its factorization.

9921915 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 7643 (or 7640 counting only the distinct ones).

The product of its digits is 7290, while the sum is 36.

The square root of 9921915 is about 3149.9071414885. The cubic root of 9921915 is about 214.8812396220.

The spelling of 9921915 in words is "nine million, nine hundred twenty-one thousand, nine hundred fifteen".