15905 has 4 divisors (see below), whose sum is σ = 19092. Its totient is φ = 12720.

The previous prime is 15901. The next prime is 15907. The reversal of 15905 is 50951.

15905 is nontrivially palindromic in base 9.

15905 is digitally balanced in base 2, base 3 and base 6, because in such bases it contains all the possibile digits an equal number of times.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 3136 + 12769 = 56^2 + 113^2 .

It is not a de Polignac number, because 15905 - 2² = 15901 is a prime.

It is a Duffinian number.

15905 is strictly pandigital in base 6.

It is not an unprimeable number, because it can be changed into a prime (15901) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (7) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1586 + ... + 1595.

It is an arithmetic number, because the mean of its divisors is an integer number (4773).

2¹⁵⁹⁰⁵ is an apocalyptic number.

It is an amenable number.

15905 is a deficient number, since it is larger than the sum of its proper divisors (3187).

15905 is an equidigital number, since it uses as much as digits as its factorization.

15905 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3186.

The product of its (nonzero) digits is 225, while the sum is 20.

The square root of 15905 is about 126.1150268604. The cubic root of 15905 is about 25.1484500914.

The spelling of 15905 in words is "fifteen thousand, nine hundred five".