11815 has 8 divisors (see below), whose sum is σ = 15120. Its totient is φ = 8832.

The previous prime is 11813. The next prime is 11821. The reversal of 11815 is 51811.

11815 is an esthetic number in base 3, because in such base its adjacent digits differ by 1.

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

It is a cyclic number.

It is not a de Polignac number, because 11815 - 2¹ = 11813 is a prime.

11815 is a lucky number.

It is a plaindrome in base 15.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (11813) 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, 16 + ... + 154.

It is an arithmetic number, because the mean of its divisors is an integer number (1890).

2¹¹⁸¹⁵ is an apocalyptic number.

11815 is a deficient number, since it is larger than the sum of its proper divisors (3305).

11815 is a wasteful number, since it uses less digits than its factorization.

11815 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 161.

The product of its digits is 40, while the sum is 16.

The square root of 11815 is about 108.6968260806. The cubic root of 11815 is about 22.7760238366.

It can be divided in two parts, 118 and 15, that multiplied together give a triangular number (1770 = T₅₉).

The spelling of 11815 in words is "eleven thousand, eight hundred fifteen".