221212231 has 4 divisors (see below), whose sum is σ = 232855000. Its totient is φ = 209569464.

The previous prime is 221212223. The next prime is 221212247. The reversal of 221212231 is 132212122.

It is a happy number.

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 221212231 - 2³ = 221212223 is a prime.

It is a super-2 number, since 2×221212231² = 97869702287994722, 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 (221212031) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 5821356 + ... + 5821393.

It is an arithmetic number, because the mean of its divisors is an integer number (58213750).

Almost surely, 2^221212231 is an apocalyptic number.

221212231 is a deficient number, since it is larger than the sum of its proper divisors (11642769).

221212231 is a wasteful number, since it uses less digits than its factorization.

221212231 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 11642768.

The product of its digits is 96, while the sum is 16.

The square root of 221212231 is about 14873.2051354105. The cubic root of 221212231 is about 604.7878326228.

Adding to 221212231 its reverse (132212122), we get a palindrome (353424353).

The spelling of 221212231 in words is "two hundred twenty-one million, two hundred twelve thousand, two hundred thirty-one".