221256 has 48 divisors (see below), whose sum is σ = 686400. Its totient is φ = 63072.

The previous prime is 221251. The next prime is 221261. The reversal of 221256 is 652122.

It is an interprime number because it is at equal distance from previous prime (221251) and next prime (221261).

It is a Harshad number since it is a multiple of its sum of digits (18).

It is not an unprimeable number, because it can be changed into a prime (221251) by changing a digit.

221256 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 11 ways as a sum of consecutive naturals, for example, 285 + ... + 723.

It is an arithmetic number, because the mean of its divisors is an integer number (14300).

2²²¹²⁵⁶ 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 221256, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (343200).

221256 is an abundant number, since it is smaller than the sum of its proper divisors (465144).

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

221256 is a wasteful number, since it uses less digits than its factorization.

221256 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 458 (or 451 counting only the distinct ones).

The product of its digits is 240, while the sum is 18.

The square root of 221256 is about 470.3785709405. The cubic root of 221256 is about 60.4827717719.

Adding to 221256 its reverse (652122), we get a palindrome (873378).

The spelling of 221256 in words is "two hundred twenty-one thousand, two hundred fifty-six".