215604 has 36 divisors (see below), whose sum is σ = 560196. Its totient is φ = 69888.

The previous prime is 215587. The next prime is 215617. The reversal of 215604 is 406512.

It is a happy number.

215604 is digitally balanced in base 3, because in such base it contains all the possibile digits an equal number of times.

It can be written as a sum of positive squares in 2 ways, for example, as 63504 + 152100 = 252^2 + 390^2 .

It is a tau number, because it is divible by the number of its divisors (36).

It is a hoax number, since the sum of its digits (18) coincides with the sum of the digits of its distinct prime factors.

It is a Harshad number since it is a multiple of its sum of digits (18).

It is a congruent number.

It is an unprimeable number.

215604 is an untouchable number, because it is not equal to the sum of proper divisors of any number.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 1852 + ... + 1964.

It is an arithmetic number, because the mean of its divisors is an integer number (15561).

2²¹⁵⁶⁰⁴ is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 215604, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (280098).

215604 is an abundant number, since it is smaller than the sum of its proper divisors (344592).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

215604 is a wasteful number, since it uses less digits than its factorization.

215604 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 176 (or 171 counting only the distinct ones).

The product of its (nonzero) digits is 240, while the sum is 18.

The square root of 215604 is about 464.3317779347. The cubic root of 215604 is about 59.9633109031.

It can be divided in two parts, 21 and 5604, that added together give a square (5625 = 75²).

The spelling of 215604 in words is "two hundred fifteen thousand, six hundred four".