213904 has 20 divisors (see below), whose sum is σ = 429660. Its totient is φ = 103040.

The previous prime is 213901. The next prime is 213919. The reversal of 213904 is 409312.

It can be written as a sum of positive squares in 2 ways, for example, as 90000 + 123904 = 300^2 + 352^2 .

It is a plaindrome in base 11.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (213901) by changing a digit.

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 3 ways as a sum of consecutive naturals, for example, 234 + ... + 694.

It is an arithmetic number, because the mean of its divisors is an integer number (21483).

2²¹³⁹⁰⁴ 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 213904, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (214830).

213904 is an abundant number, since it is smaller than the sum of its proper divisors (215756).

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

213904 is a wasteful number, since it uses less digits than its factorization.

213904 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 498 (or 492 counting only the distinct ones).

The product of its (nonzero) digits is 216, while the sum is 19.

The square root of 213904 is about 462.4975675612. The cubic root of 213904 is about 59.8052947740.

The spelling of 213904 in words is "two hundred thirteen thousand, nine hundred four".