221704 has 32 divisors (see below), whose sum is σ = 492480. Its totient is φ = 91584.

The previous prime is 221677. The next prime is 221707. The reversal of 221704 is 407122.

221704 is nontrivially palindromic in base 15.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (221707) by changing a digit.

221704 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 7 ways as a sum of consecutive naturals, for example, 2019 + ... + 2125.

It is an arithmetic number, because the mean of its divisors is an integer number (15390).

2²²¹⁷⁰⁴ 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 221704, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (246240).

221704 is an abundant number, since it is smaller than the sum of its proper divisors (270776).

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

221704 is a wasteful number, since it uses less digits than its factorization.

221704 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 157 (or 153 counting only the distinct ones).

The product of its (nonzero) digits is 112, while the sum is 16.

The square root of 221704 is about 470.8545422952. The cubic root of 221704 is about 60.5235661670.

Adding to 221704 its reverse (407122), we get a palindrome (628826).

The spelling of 221704 in words is "two hundred twenty-one thousand, seven hundred four", and thus it is an iban number.