9815 has 8 divisors (see below), whose sum is σ = 12768. Its totient is φ = 7200.

The previous prime is 9811. The next prime is 9817. The reversal of 9815 is 5189.

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

It is not a de Polignac number, because 9815 - 2² = 9811 is a prime.

It is a Duffinian number.

It is a congruent number.

It is an inconsummate number, since it does not exist a number n which divided by its sum of digits gives 9815.

It is not an unprimeable number, because it can be changed into a prime (9811) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 11 + ... + 140.

It is an arithmetic number, because the mean of its divisors is an integer number (1596).

2⁹⁸¹⁵ is an apocalyptic number.

9815 is a deficient number, since it is larger than the sum of its proper divisors (2953).

9815 is a wasteful number, since it uses less digits than its factorization.

9815 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 169.

The product of its digits is 360, while the sum is 23.

The square root of 9815 is about 99.0706818388. The cubic root of 9815 is about 21.4106622851.

The spelling of 9815 in words is "nine thousand, eight hundred fifteen".