999689666 has 8 divisors (see below), whose sum is σ = 1500572304. Its totient is φ = 499498900.

The previous prime is 999689629. The next prime is 999689681. The reversal of 999689666 is 666986999.

999689666 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

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

999689666 is a strobogrammatic number because it is the same when read upside-down.

It is a junction number, because it is equal to n+sod(n) for n = 999689596 and 999689605.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 169340 + ... + 175143.

It is an arithmetic number, because the mean of its divisors is an integer number (187571538).

Almost surely, 2^999689666 is an apocalyptic number.

999689666 is a deficient number, since it is larger than the sum of its proper divisors (500882638).

999689666 is a wasteful number, since it uses less digits than its factorization.

999689666 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 345936.

The product of its digits is 68024448, while the sum is 68.

The square root of 999689666 is about 31617.8694095602. The cubic root of 999689666 is about 999.8965446307.

The spelling of 999689666 in words is "nine hundred ninety-nine million, six hundred eighty-nine thousand, six hundred sixty-six".