105815 has 4 divisors (see below), whose sum is σ = 126984. Its totient is φ = 84648.

The previous prime is 105769. The next prime is 105817. The reversal of 105815 is 518501.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 518501 = 83 ⋅6247.

It is a cyclic number.

It is not a de Polignac number, because 105815 - 2⁶ = 105751 is a prime.

It is a super-2 number, since 2×105815² = 22393628450, which contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (105817) by changing a digit.

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 3 ways as a sum of consecutive naturals, for example, 10577 + ... + 10586.

It is an arithmetic number, because the mean of its divisors is an integer number (31746).

2¹⁰⁵⁸¹⁵ is an apocalyptic number.

105815 is a deficient number, since it is larger than the sum of its proper divisors (21169).

105815 is an equidigital number, since it uses as much as digits as its factorization.

105815 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 21168.

The product of its (nonzero) digits is 200, while the sum is 20.

The square root of 105815 is about 325.2921763584. The cubic root of 105815 is about 47.2986863207.

Subtracting 105815 from its reverse (518501), we obtain a triangular number (412686 = T₉₀₈).

The spelling of 105815 in words is "one hundred five thousand, eight hundred fifteen".