16399999 has 8 divisors (see below), whose sum is σ = 20446848. Its totient is φ = 12779160.

The previous prime is 16399987. The next prime is 16400017. The reversal of 16399999 is 99999361.

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

It is a cyclic number.

It is not a de Polignac number, because 16399999 - 2⁵ = 16399967 is a prime.

It is a Duffinian number.

16399999 is a modest number, since divided by 9999 gives 1639 as remainder.

It is a congruent number.

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 in 7 ways as a sum of consecutive naturals, for example, 106417 + ... + 106570.

It is an arithmetic number, because the mean of its divisors is an integer number (2555856).

Almost surely, 2^16399999 is an apocalyptic number.

16399999 is a deficient number, since it is larger than the sum of its proper divisors (4046849).

16399999 is a wasteful number, since it uses less digits than its factorization.

16399999 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 213005.

The product of its digits is 1062882, while the sum is 55.

The square root of 16399999 is about 4049.6912227971. The cubic root of 16399999 is about 254.0668133905.

It can be divided in two parts, 1639 and 9999, that multiplied together give a palindrome (16388361).

The spelling of 16399999 in words is "sixteen million, three hundred ninety-nine thousand, nine hundred ninety-nine".