999969999 has 24 divisors (see below), whose sum is σ = 1552168368. Its totient is φ = 570971520.

The previous prime is 999969991. The next prime is 999970003.

999969999 is nontrivially palindromic in base 10.

It is not a de Polignac number, because 999969999 - 2³ = 999969991 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (999969991) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 348579 + ... + 351435.

It is an arithmetic number, because the mean of its divisors is an integer number (64673682).

Almost surely, 2^999969999 is an apocalyptic number.

999969999 is a deficient number, since it is larger than the sum of its proper divisors (552198369).

999969999 is a wasteful number, since it uses less digits than its factorization.

999969999 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5255 (or 5248 counting only the distinct ones).

The product of its digits is 258280326, while the sum is 78.

The square root of 999969999 is about 31622.3022406655. The cubic root of 999969999 is about 999.9899995667.

The spelling of 999969999 in words is "nine hundred ninety-nine million, nine hundred sixty-nine thousand, nine hundred ninety-nine".