9915 has 8 divisors (see below), whose sum is σ = 15888. Its totient is φ = 5280.

The previous prime is 9907. The next prime is 9923. The reversal of 9915 is 5199.

It is a happy number.

9915 is nontrivially palindromic in base 14.

It is an interprime number because it is at equal distance from previous prime (9907) and next prime (9923).

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 9915 - 2³ = 9907 is a prime.

9915 is a lucky number.

It is a plaindrome in base 13 and base 16.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 316 + ... + 345.

It is an arithmetic number, because the mean of its divisors is an integer number (1986).

2⁹⁹¹⁵ is an apocalyptic number.

9915 is a deficient number, since it is larger than the sum of its proper divisors (5973).

9915 is a wasteful number, since it uses less digits than its factorization.

9915 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 669.

The product of its digits is 405, while the sum is 24.

The square root of 9915 is about 99.5740930162. The cubic root of 9915 is about 21.4831308095.

It can be divided in two parts, 99 and 15, that multiplied together give a triangular number (1485 = T₅₄).

The spelling of 9915 in words is "nine thousand, nine hundred fifteen".