666699 has 16 divisors (see below), whose sum is σ = 984960. Its totient is φ = 397760.

The previous prime is 666697. The next prime is 666707. The reversal of 666699 is 996666.

It is not a de Polignac number, because 666699 - 2¹ = 666697 is a prime.

666699 is a lucky number.

It is a plaindrome in base 10.

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 666699.

It is not an unprimeable number, because it can be changed into a prime (666697) 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, 2824 + ... + 3050.

It is an arithmetic number, because the mean of its divisors is an integer number (61560).

2⁶⁶⁶⁶⁹⁹ is an apocalyptic number.

666699 is a deficient number, since it is larger than the sum of its proper divisors (318261).

666699 is a wasteful number, since it uses less digits than its factorization.

666699 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 330.

The product of its digits is 104976, while the sum is 42.

The square root of 666699 is about 816.5163807297. The cubic root of 666699 is about 87.3594587392.

The spelling of 666699 in words is "six hundred sixty-six thousand, six hundred ninety-nine".