999966999 has 16 divisors (see below), whose sum is σ = 1366928640. Its totient is φ = 649851840.

The previous prime is 999966997. The next prime is 999967037. The reversal of 999966999 is 999669999.

It is not a de Polignac number, because 999966999 - 2¹ = 999966997 is a prime.

It is a zygodrome in base 10.

It is a self number, because there is not a number n which added to its sum of digits gives 999966999.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (999966997) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 195132 + ... + 200190.

It is an arithmetic number, because the mean of its divisors is an integer number (85433040).

Almost surely, 2^999966999 is an apocalyptic number.

999966999 is a deficient number, since it is larger than the sum of its proper divisors (366961641).

999966999 is a wasteful number, since it uses less digits than its factorization.

999966999 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 6710.

The product of its digits is 172186884, while the sum is 75.

The square root of 999966999 is about 31622.2548057535. The cubic root of 999966999 is about 999.9889995457.

The spelling of 999966999 in words is "nine hundred ninety-nine million, nine hundred sixty-six thousand, nine hundred ninety-nine".