19842209 has 2 divisors, whose sum is σ = 19842210. Its totient is φ = 19842208.

The previous prime is 19842191. The next prime is 19842217. The reversal of 19842209 is 90224891.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 19536400 + 305809 = 4420^2 + 553^2 .

It is a cyclic number.

It is not a de Polignac number, because 19842209 - 2¹² = 19838113 is a prime.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (19842239) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 9921104 + 9921105.

It is an arithmetic number, because the mean of its divisors is an integer number (9921105).

Almost surely, 2^19842209 is an apocalyptic number.

It is an amenable number.

19842209 is a deficient number, since it is larger than the sum of its proper divisors (1).

19842209 is an equidigital number, since it uses as much as digits as its factorization.

19842209 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 10368, while the sum is 35.

The square root of 19842209 is about 4454.4594509323. The cubic root of 19842209 is about 270.7260249492.

The spelling of 19842209 in words is "nineteen million, eight hundred forty-two thousand, two hundred nine".