217904 has 10 divisors (see below), whose sum is σ = 422220. Its totient is φ = 108944.

The previous prime is 217901. The next prime is 217907. The reversal of 217904 is 409712.

217904 is digitally balanced in base 3, because in such base it contains all the possibile digits an equal number of times.

It is an interprime number because it is at equal distance from previous prime (217901) and next prime (217907).

It is a self number, because there is not a number n which added to its sum of digits gives 217904.

It is not an unprimeable number, because it can be changed into a prime (217901) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 6794 + ... + 6825.

It is an arithmetic number, because the mean of its divisors is an integer number (42222).

2²¹⁷⁹⁰⁴ is an apocalyptic number.

It is an amenable number.

217904 is a deficient number, since it is larger than the sum of its proper divisors (204316).

217904 is a wasteful number, since it uses less digits than its factorization.

217904 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 13627 (or 13621 counting only the distinct ones).

The product of its (nonzero) digits is 504, while the sum is 23.

The square root of 217904 is about 466.8018851719. The cubic root of 217904 is about 60.1757808118.

The spelling of 217904 in words is "two hundred seventeen thousand, nine hundred four".