221285 has 4 divisors (see below), whose sum is σ = 265548. Its totient is φ = 177024.

The previous prime is 221281. The next prime is 221303. The reversal of 221285 is 582122.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 155236 + 66049 = 394^2 + 257^2 .

It is a cyclic number.

It is not a de Polignac number, because 221285 - 2² = 221281 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (221281) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 22124 + ... + 22133.

It is an arithmetic number, because the mean of its divisors is an integer number (66387).

2²²¹²⁸⁵ is an apocalyptic number.

It is an amenable number.

221285 is a deficient number, since it is larger than the sum of its proper divisors (44263).

221285 is an equidigital number, since it uses as much as digits as its factorization.

221285 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 44262.

The product of its digits is 320, while the sum is 20.

The square root of 221285 is about 470.4093961647. The cubic root of 221285 is about 60.4854141465.

The spelling of 221285 in words is "two hundred twenty-one thousand, two hundred eighty-five".