16809999 has 8 divisors (see below), whose sum is σ = 22435200. Its totient is φ = 11195736.

The previous prime is 16809997. The next prime is 16810007. The reversal of 16809999 is 99990861.

It is a Cunningham number, because it is equal to 4100²-1.

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 16809999 - 2¹ = 16809997 is a prime.

16809999 is a modest number, since divided by 9999 gives 1680 as remainder.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (16809997) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 2052 + ... + 6150.

It is an arithmetic number, because the mean of its divisors is an integer number (2804400).

Almost surely, 2^16809999 is an apocalyptic number.

16809999 is a deficient number, since it is larger than the sum of its proper divisors (5625201).

16809999 is a wasteful number, since it uses less digits than its factorization.

16809999 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5469.

The product of its (nonzero) digits is 314928, while the sum is 51.

The square root of 16809999 is about 4099.9998780488. Note that the first 3 decimals coincide. The cubic root of 16809999 is about 256.1666344720.

The spelling of 16809999 in words is "sixteen million, eight hundred nine thousand, nine hundred ninety-nine".