16399904 has 12 divisors (see below), whose sum is σ = 32287374. Its totient is φ = 8199936.

The previous prime is 16399871. The next prime is 16399909. The reversal of 16399904 is 40999361.

16399904 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It can be written as a sum of positive squares in only one way, i.e., 15840400 + 559504 = 3980^2 + 748^2 .

It is not an unprimeable number, because it can be changed into a prime (16399909) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 256217 + ... + 256280.

Almost surely, 2^16399904 is an apocalyptic number.

It is an amenable number.

16399904 is a deficient number, since it is larger than the sum of its proper divisors (15887470).

16399904 is an equidigital number, since it uses as much as digits as its factorization.

16399904 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 512507 (or 512499 counting only the distinct ones).

The product of its (nonzero) digits is 52488, while the sum is 41.

The square root of 16399904 is about 4049.6794934908. The cubic root of 16399904 is about 254.0663228134.

The spelling of 16399904 in words is "sixteen million, three hundred ninety-nine thousand, nine hundred four".