221231 has 4 divisors (see below), whose sum is σ = 222552. Its totient is φ = 219912.

The previous prime is 221227. The next prime is 221233. The reversal of 221231 is 132122.

It is a happy number.

221231 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

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

It is a cyclic number.

It is not a de Polignac number, because 221231 - 2² = 221227 is a prime.

It is a super-2 number, since 2×221231² = 97886310722, which contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (221233) 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, 365 + ... + 758.

It is an arithmetic number, because the mean of its divisors is an integer number (55638).

2²²¹²³¹ is an apocalyptic number.

221231 is a deficient number, since it is larger than the sum of its proper divisors (1321).

221231 is a wasteful number, since it uses less digits than its factorization.

221231 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1320.

The product of its digits is 24, while the sum is 11.

The square root of 221231 is about 470.3519958499. The cubic root of 221231 is about 60.4804936773.

Adding to 221231 its reverse (132122), we get a palindrome (353353).

The spelling of 221231 in words is "two hundred twenty-one thousand, two hundred thirty-one".