220431221 has 2 divisors, whose sum is σ = 220431222. Its totient is φ = 220431220.

The previous prime is 220431193. The next prime is 220431223. The reversal of 220431221 is 122134022.

220431221 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 213598225 + 6832996 = 14615^2 + 2614^2 .

It is a cyclic number.

It is not a de Polignac number, because 220431221 - 2⁶ = 220431157 is a prime.

Together with 220431223, it forms a pair of twin primes.

It is a Chen prime.

It is a self number, because there is not a number n which added to its sum of digits gives 220431221.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (220431223) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 110215610 + 110215611.

It is an arithmetic number, because the mean of its divisors is an integer number (110215611).

Almost surely, 2^220431221 is an apocalyptic number.

It is an amenable number.

220431221 is a deficient number, since it is larger than the sum of its proper divisors (1).

220431221 is an equidigital number, since it uses as much as digits as its factorization.

220431221 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 192, while the sum is 17.

The square root of 220431221 is about 14846.9263148976. The cubic root of 220431221 is about 604.0752404332.

Adding to 220431221 its reverse (122134022), we get a palindrome (342565243).

The spelling of 220431221 in words is "two hundred twenty million, four hundred thirty-one thousand, two hundred twenty-one".