213605 has 16 divisors (see below), whose sum is σ = 311040. Its totient is φ = 137472.

The previous prime is 213599. The next prime is 213611. The reversal of 213605 is 506312.

It is an interprime number because it is at equal distance from previous prime (213599) and next prime (213611).

It is a cyclic number.

It is not a de Polignac number, because 213605 - 2⁴ = 213589 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (17).

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 213605.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 416 + ... + 774.

It is an arithmetic number, because the mean of its divisors is an integer number (19440).

2²¹³⁶⁰⁵ is an apocalyptic number.

It is an amenable number.

213605 is a deficient number, since it is larger than the sum of its proper divisors (97435).

213605 is a wasteful number, since it uses less digits than its factorization.

213605 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 388.

The product of its (nonzero) digits is 180, while the sum is 17.

The square root of 213605 is about 462.1742095790. The cubic root of 213605 is about 59.7774160348. Note that the first 3 decimals are identical.

Adding to 213605 its reverse (506312), we get a palindrome (719917).

It can be divided in two parts, 213 and 605, that added together give a palindrome (818).

The spelling of 213605 in words is "two hundred thirteen thousand, six hundred five".