16859221 has 2 divisors, whose sum is σ = 16859222. Its totient is φ = 16859220.

The previous prime is 16859203. The next prime is 16859233. The reversal of 16859221 is 12295861.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 14938225 + 1920996 = 3865^2 + 1386^2 .

It is an emirp because it is prime and its reverse (12295861) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 16859221 - 2⁷ = 16859093 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (16859281) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (7) of ones.

It is a good prime.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 8429610 + 8429611.

It is an arithmetic number, because the mean of its divisors is an integer number (8429611).

Almost surely, 2^16859221 is an apocalyptic number.

It is an amenable number.

16859221 is a deficient number, since it is larger than the sum of its proper divisors (1).

16859221 is an equidigital number, since it uses as much as digits as its factorization.

16859221 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 8640, while the sum is 34.

The square root of 16859221 is about 4105.9981734044. The cubic root of 16859221 is about 256.4164212619.

The spelling of 16859221 in words is "sixteen million, eight hundred fifty-nine thousand, two hundred twenty-one".