17990999 has 4 divisors (see below), whose sum is σ = 19374936. Its totient is φ = 16607064.

The previous prime is 17990983. The next prime is 17991007. The reversal of 17990999 is 99909971.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 17990999 - 2⁴ = 17990983 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 17990999.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (17990939) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 691949 + ... + 691974.

It is an arithmetic number, because the mean of its divisors is an integer number (4843734).

Almost surely, 2^17990999 is an apocalyptic number.

17990999 is a deficient number, since it is larger than the sum of its proper divisors (1383937).

17990999 is a wasteful number, since it uses less digits than its factorization.

17990999 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1383936.

The product of its (nonzero) digits is 413343, while the sum is 53.

The square root of 17990999 is about 4241.5797764512. The cubic root of 17990999 is about 262.0304482609.

The spelling of 17990999 in words is "seventeen million, nine hundred ninety thousand, nine hundred ninety-nine".