421403221 has 2 divisors, whose sum is σ = 421403222. Its totient is φ = 421403220.

The previous prime is 421403219. The next prime is 421403251. The reversal of 421403221 is 122304124.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 244140625 + 177262596 = 15625^2 + 13314^2 .

It is a cyclic number.

It is not a de Polignac number, because 421403221 - 2¹ = 421403219 is a prime.

Together with 421403219, it forms a pair of twin primes.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (421403251) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 210701610 + 210701611.

It is an arithmetic number, because the mean of its divisors is an integer number (210701611).

Almost surely, 2^421403221 is an apocalyptic number.

It is an amenable number.

421403221 is a deficient number, since it is larger than the sum of its proper divisors (1).

421403221 is an equidigital number, since it uses as much as digits as its factorization.

421403221 is an evil number, because the sum of its binary digits is even.

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

The square root of 421403221 is about 20528.1080716173. The cubic root of 421403221 is about 749.7203229799.

Adding to 421403221 its reverse (122304124), we get a palindrome (543707345).

The spelling of 421403221 in words is "four hundred twenty-one million, four hundred three thousand, two hundred twenty-one".