215222221 has 2 divisors, whose sum is σ = 215222222. Its totient is φ = 215222220.

The previous prime is 215222197. The next prime is 215222233. The reversal of 215222221 is 122222512.

215222221 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., 213014025 + 2208196 = 14595^2 + 1486^2 .

It is a cyclic number.

It is not a de Polignac number, because 215222221 - 2⁷ = 215222093 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (215222251) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 107611110 + 107611111.

It is an arithmetic number, because the mean of its divisors is an integer number (107611111).

Almost surely, 2^215222221 is an apocalyptic number.

It is an amenable number.

215222221 is a deficient number, since it is larger than the sum of its proper divisors (1).

215222221 is an equidigital number, since it uses as much as digits as its factorization.

215222221 is an evil number, because the sum of its binary digits is even.

The product of its digits is 320, while the sum is 19.

The square root of 215222221 is about 14670.4540147877. The cubic root of 215222221 is about 599.2789681281.

Adding to 215222221 its reverse (122222512), we get a palindrome (337444733).

The spelling of 215222221 in words is "two hundred fifteen million, two hundred twenty-two thousand, two hundred twenty-one".