19994399 has 4 divisors (see below), whose sum is σ = 20147160. Its totient is φ = 19841640.

The previous prime is 19994389. The next prime is 19994407. The reversal of 19994399 is 99349991.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 19994399 - 2¹² = 19990303 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 19994399.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (19994309) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 76184 + ... + 76445.

It is an arithmetic number, because the mean of its divisors is an integer number (5036790).

Almost surely, 2^19994399 is an apocalyptic number.

19994399 is a deficient number, since it is larger than the sum of its proper divisors (152761).

19994399 is a wasteful number, since it uses less digits than its factorization.

19994399 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 152760.

The product of its digits is 708588, while the sum is 53.

The square root of 19994399 is about 4471.5097003138. The cubic root of 19994399 is about 271.4164202053.

The spelling of 19994399 in words is "nineteen million, nine hundred ninety-four thousand, three hundred ninety-nine".