221944409 has 2 divisors, whose sum is σ = 221944410. Its totient is φ = 221944408.

The previous prime is 221944399. The next prime is 221944423. The reversal of 221944409 is 904449122.

It is a happy number.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 154753600 + 67190809 = 12440^2 + 8197^2 .

It is a cyclic number.

It is not a de Polignac number, because 221944409 - 2²⁰ = 220895833 is a prime.

It is a weakly prime.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 110972204 + 110972205.

It is an arithmetic number, because the mean of its divisors is an integer number (110972205).

Almost surely, 2^221944409 is an apocalyptic number.

It is an amenable number.

221944409 is a deficient number, since it is larger than the sum of its proper divisors (1).

221944409 is an equidigital number, since it uses as much as digits as its factorization.

221944409 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 20736, while the sum is 35.

The square root of 221944409 is about 14897.7987971378. The cubic root of 221944409 is about 605.4543489565.

The spelling of 221944409 in words is "two hundred twenty-one million, nine hundred forty-four thousand, four hundred nine".