221223209 has 2 divisors, whose sum is σ = 221223210. Its totient is φ = 221223208.

The previous prime is 221223203. The next prime is 221223221. The reversal of 221223209 is 902322122.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 147744025 + 73479184 = 12155^2 + 8572^2 .

It is a cyclic number.

It is not a de Polignac number, because 221223209 - 2²⁴ = 204445993 is a prime.

It is not a weakly prime, because it can be changed into another prime (221223203) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 110611604 + 110611605.

It is an arithmetic number, because the mean of its divisors is an integer number (110611605).

Almost surely, 2^221223209 is an apocalyptic number.

It is an amenable number.

221223209 is a deficient number, since it is larger than the sum of its proper divisors (1).

221223209 is an equidigital number, since it uses as much as digits as its factorization.

221223209 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 864, while the sum is 23.

The square root of 221223209 is about 14873.5741837663. The cubic root of 221223209 is about 604.7978369687.

The spelling of 221223209 in words is "two hundred twenty-one million, two hundred twenty-three thousand, two hundred nine".