13605 has 8 divisors (see below), whose sum is σ = 21792. Its totient is φ = 7248.

The previous prime is 13597. The next prime is 13613. The reversal of 13605 is 50631.

13605 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is an interprime number because it is at equal distance from previous prime (13597) and next prime (13613).

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

It is not a de Polignac number, because 13605 - 2³ = 13597 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (15), and also a Moran number because the ratio is a prime number: 907 = 13605 / (1 + 3 + 6 + 0 + 5).

It is a Curzon number.

It is a nialpdrome in base 7.

It is a congruent number.

It is an unprimeable number.

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 7 ways as a sum of consecutive naturals, for example, 439 + ... + 468.

It is an arithmetic number, because the mean of its divisors is an integer number (2724).

2¹³⁶⁰⁵ is an apocalyptic number.

13605 is a gapful number since it is divisible by the number (15) formed by its first and last digit.

It is an amenable number.

13605 is a deficient number, since it is larger than the sum of its proper divisors (8187).

13605 is an equidigital number, since it uses as much as digits as its factorization.

13605 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 915.

The product of its (nonzero) digits is 90, while the sum is 15.

The square root of 13605 is about 116.6404732501. The cubic root of 13605 is about 23.8725886840.

Adding to 13605 its product of nonzero digits (90), we get a triangular number (13695 = T₁₆₅).

The spelling of 13605 in words is "thirteen thousand, six hundred five".