221606393 has 2 divisors, whose sum is σ = 221606394. Its totient is φ = 221606392.

The previous prime is 221606327. The next prime is 221606417. The reversal of 221606393 is 393606122.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 171295744 + 50310649 = 13088^2 + 7093^2 .

It is a cyclic number.

It is not a de Polignac number, because 221606393 - 2¹⁴ = 221590009 is a prime.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (221606093) 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 as a sum of consecutive naturals, namely, 110803196 + 110803197.

It is an arithmetic number, because the mean of its divisors is an integer number (110803197).

Almost surely, 2^221606393 is an apocalyptic number.

It is an amenable number.

221606393 is a deficient number, since it is larger than the sum of its proper divisors (1).

221606393 is an equidigital number, since it uses as much as digits as its factorization.

221606393 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 11664, while the sum is 32.

The square root of 221606393 is about 14886.4499797635. The cubic root of 221606393 is about 605.1468286482.

The spelling of 221606393 in words is "two hundred twenty-one million, six hundred six thousand, three hundred ninety-three".