19993209 has 16 divisors (see below), whose sum is σ = 28326720. Its totient is φ = 12519360.

The previous prime is 19993201. The next prime is 19993219. The reversal of 19993209 is 90239991.

It is a happy number.

It is not a de Polignac number, because 19993209 - 2³ = 19993201 is a prime.

It is a super-2 number, since 2×19993209² = 799456812235362, which contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (19993201) 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 in 15 ways as a sum of consecutive naturals, for example, 114 + ... + 6324.

It is an arithmetic number, because the mean of its divisors is an integer number (1770420).

Almost surely, 2^19993209 is an apocalyptic number.

It is an amenable number.

19993209 is a deficient number, since it is larger than the sum of its proper divisors (8333511).

19993209 is a wasteful number, since it uses less digits than its factorization.

19993209 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 6280.

The product of its (nonzero) digits is 39366, while the sum is 42.

The square root of 19993209 is about 4471.3766336555. The cubic root of 19993209 is about 271.4110354981.

It can be divided in two parts, 19993 and 209, that added together give a palindrome (20202).

The spelling of 19993209 in words is "nineteen million, nine hundred ninety-three thousand, two hundred nine".