221331 has 16 divisors (see below), whose sum is σ = 339840. Its totient is φ = 126720.

The previous prime is 221327. The next prime is 221393. The reversal of 221331 is 133122.

It is a happy number.

It is not a de Polignac number, because 221331 - 2² = 221327 is a prime.

It is a super-2 number, since 2×221331² = 97974823122, which contains 22 as substring.

It is a congruent number.

It is an inconsummate number, since it does not exist a number n which divided by its sum of digits gives 221331.

It is not an unprimeable number, because it can be changed into a prime (221311) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 451 + ... + 803.

It is an arithmetic number, because the mean of its divisors is an integer number (21240).

2²²¹³³¹ is an apocalyptic number.

221331 is a deficient number, since it is larger than the sum of its proper divisors (118509).

221331 is a wasteful number, since it uses less digits than its factorization.

221331 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 386.

The product of its digits is 36, while the sum is 12.

The square root of 221331 is about 470.4582872051. The cubic root of 221331 is about 60.4896050260.

Adding to 221331 its reverse (133122), we get a palindrome (354453).

Subtracting from 221331 its reverse (133122), we obtain a square (88209 = 297²).

The spelling of 221331 in words is "two hundred twenty-one thousand, three hundred thirty-one".