221223421 has 2 divisors, whose sum is σ = 221223422. Its totient is φ = 221223420.

The previous prime is 221223371. The next prime is 221223451. The reversal of 221223421 is 124322122.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 212139225 + 9084196 = 14565^2 + 3014^2 .

It is a cyclic number.

It is not a de Polignac number, because 221223421 - 2⁷ = 221223293 is a prime.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (221223451) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 110611710 + 110611711.

It is an arithmetic number, because the mean of its divisors is an integer number (110611711).

Almost surely, 2^221223421 is an apocalyptic number.

It is an amenable number.

221223421 is a deficient number, since it is larger than the sum of its proper divisors (1).

221223421 is an equidigital number, since it uses as much as digits as its factorization.

221223421 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 384, while the sum is 19.

The square root of 221223421 is about 14873.5813104982. The cubic root of 221223421 is about 604.7980301629.

Adding to 221223421 its reverse (124322122), we get a palindrome (345545543).

The spelling of 221223421 in words is "two hundred twenty-one million, two hundred twenty-three thousand, four hundred twenty-one".