15605 has 4 divisors (see below), whose sum is σ = 18732. Its totient is φ = 12480.

The previous prime is 15601. The next prime is 15607. The reversal of 15605 is 50651.

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 1681 + 13924 = 41^2 + 118^2 .

It is not a de Polignac number, because 15605 - 2² = 15601 is a prime.

It is a Duffinian number.

It is a plaindrome in base 9.

It is a nialpdrome in base 5 and base 7.

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 15605.

It is not an unprimeable number, because it can be changed into a prime (15601) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1556 + ... + 1565.

It is an arithmetic number, because the mean of its divisors is an integer number (4683).

2¹⁵⁶⁰⁵ is an apocalyptic number.

It is an amenable number.

15605 is a deficient number, since it is larger than the sum of its proper divisors (3127).

15605 is an equidigital number, since it uses as much as digits as its factorization.

15605 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3126.

The product of its (nonzero) digits is 150, while the sum is 17.

The square root of 15605 is about 124.9199743836. The cubic root of 15605 is about 24.9893287790.

The spelling of 15605 in words is "fifteen thousand, six hundred five".