19994209 has 4 divisors (see below), whose sum is σ = 20018880. Its totient is φ = 19969540.

The previous prime is 19994201. The next prime is 19994237. The reversal of 19994209 is 90249991.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 19994209 - 2³ = 19994201 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (19994201) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 11077 + ... + 12754.

It is an arithmetic number, because the mean of its divisors is an integer number (5004720).

Almost surely, 2^19994209 is an apocalyptic number.

It is an amenable number.

19994209 is a deficient number, since it is larger than the sum of its proper divisors (24671).

19994209 is an equidigital number, since it uses as much as digits as its factorization.

19994209 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 24670.

The product of its (nonzero) digits is 52488, while the sum is 43.

The square root of 19994209 is about 4471.4884546424. The cubic root of 19994209 is about 271.4155604764.

The spelling of 19994209 in words is "nineteen million, nine hundred ninety-four thousand, two hundred nine".