213645 has 8 divisors (see below), whose sum is σ = 341856. Its totient is φ = 113936.

The previous prime is 213641. The next prime is 213649. The reversal of 213645 is 546312.

It is a happy number.

It is an interprime number because it is at equal distance from previous prime (213641) and next prime (213649).

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

It is a cyclic number.

It is not a de Polignac number, because 213645 - 2² = 213641 is a prime.

It is a super-3 number, since 3×213645³ = 29254956369933375, which contains 333 as substring.

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 213645.

It is not an unprimeable number, because it can be changed into a prime (213641) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 7107 + ... + 7136.

It is an arithmetic number, because the mean of its divisors is an integer number (42732).

2²¹³⁶⁴⁵ is an apocalyptic number.

It is an amenable number.

213645 is a deficient number, since it is larger than the sum of its proper divisors (128211).

213645 is a wasteful number, since it uses less digits than its factorization.

213645 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 14251.

The product of its digits is 720, while the sum is 21.

The square root of 213645 is about 462.2174812791. The cubic root of 213645 is about 59.7811471388.

Adding to 213645 its reverse (546312), we get a palindrome (759957).

It can be divided in two parts, 213 and 645, that added together give a palindrome (858).

The spelling of 213645 in words is "two hundred thirteen thousand, six hundred forty-five".