19904399 has 16 divisors (see below), whose sum is σ = 21919392. Its totient is φ = 17998848.

The previous prime is 19904377. The next prime is 19904413. The reversal of 19904399 is 99340991.

It is a cyclic number.

It is not a de Polignac number, because 19904399 - 2¹² = 19900303 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (19904999) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 53177 + ... + 53549.

It is an arithmetic number, because the mean of its divisors is an integer number (1369962).

Almost surely, 2^19904399 is an apocalyptic number.

19904399 is a deficient number, since it is larger than the sum of its proper divisors (2014993).

19904399 is a wasteful number, since it uses less digits than its factorization.

19904399 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 506.

The product of its (nonzero) digits is 78732, while the sum is 44.

The square root of 19904399 is about 4461.4346347335. The cubic root of 19904399 is about 271.0085689660.

The spelling of 19904399 in words is "nineteen million, nine hundred four thousand, three hundred ninety-nine".