13815 has 12 divisors (see below), whose sum is σ = 24024. Its totient is φ = 7344.
The previous prime is 13807. The next prime is 13829. The reversal of 13815 is 51831.
It is a happy number.
It is not a de Polignac number, because 13815 - 23 = 13807 is a prime.
It is a hoax number, since the sum of its digits (18) coincides with the sum of the digits of its distinct prime factors.
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 13815.
It is an unprimeable number.
It is a pernicious number, because its binary representation contains a prime number (11) of ones.
It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 109 + ... + 198.
It is an arithmetic number, because the mean of its divisors is an integer number (2002).
213815 is an apocalyptic number.
13815 is a gapful number since it is divisible by the number (15) formed by its first and last digit.
13815 is a deficient number, since it is larger than the sum of its proper divisors (10209).
13815 is a wasteful number, since it uses less digits than its factorization.
13815 is an odious number, because the sum of its binary digits is odd.
The sum of its prime factors is 318 (or 315 counting only the distinct ones).
The product of its digits is 120, while the sum is 18.
The square root of 13815 is about 117.5372281450. The cubic root of 13815 is about 23.9947905360.
Subtracting from 13815 its product of digits (120), we obtain a triangular number (13695 = T165).
It can be divided in two parts, 138 and 15, that added together give a triangular number (153 = T17).
The spelling of 13815 in words is "thirteen thousand, eight hundred fifteen".
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