213604 has 6 divisors (see below), whose sum is σ = 373814. Its totient is φ = 106800.

The previous prime is 213599. The next prime is 213611. The reversal of 213604 is 406312.

213604 is an esthetic number in base 15, because in such base its adjacent digits differ by 1.

It can be written as a sum of positive squares in only one way, i.e., 152100 + 61504 = 390^2 + 248^2 .

It is an unprimeable number.

213604 is an untouchable number, because it is not equal to the sum of proper divisors of any 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 as a sum of consecutive naturals, namely, 26697 + ... + 26704.

2²¹³⁶⁰⁴ is an apocalyptic number.

It is an amenable number.

213604 is a deficient number, since it is larger than the sum of its proper divisors (160210).

213604 is a wasteful number, since it uses less digits than its factorization.

213604 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 53405 (or 53403 counting only the distinct ones).

The product of its (nonzero) digits is 144, while the sum is 16.

The square root of 213604 is about 462.1731277346. The cubic root of 213604 is about 59.7773227512. Note that the first 3 decimals are identical.

Adding to 213604 its reverse (406312), we get a palindrome (619916).

The spelling of 213604 in words is "two hundred thirteen thousand, six hundred four".