16399985 has 32 divisors (see below), whose sum is σ = 24406272. Its totient is φ = 10321920.

The previous prime is 16399979. The next prime is 16399987. The reversal of 16399985 is 58999361.

It is not a de Polignac number, because 16399985 - 2⁸ = 16399729 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (16399987) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 25265 + ... + 25905.

It is an arithmetic number, because the mean of its divisors is an integer number (762696).

Almost surely, 2^16399985 is an apocalyptic number.

It is an amenable number.

16399985 is a deficient number, since it is larger than the sum of its proper divisors (8006287).

16399985 is a wasteful number, since it uses less digits than its factorization.

16399985 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 713.

The product of its digits is 524880, while the sum is 50.

The square root of 16399985 is about 4049.6894942699. The cubic root of 16399985 is about 254.0667410951.

The spelling of 16399985 in words is "sixteen million, three hundred ninety-nine thousand, nine hundred eighty-five".