666099 has 24 divisors (see below), whose sum is σ = 1121120. Its totient is φ = 373248.

The previous prime is 666091. The next prime is 666109. The reversal of 666099 is 990666.

It is not a de Polignac number, because 666099 - 2³ = 666091 is a prime.

It is a hoax number, since the sum of its digits (36) coincides with the sum of the digits of its distinct prime factors.

It is not an unprimeable number, because it can be changed into a prime (666091) 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 23 ways as a sum of consecutive naturals, for example, 6057 + ... + 6165.

2⁶⁶⁶⁰⁹⁹ is an apocalyptic number.

666099 is a deficient number, since it is larger than the sum of its proper divisors (455021).

666099 is a wasteful number, since it uses less digits than its factorization.

666099 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 219 (or 216 counting only the distinct ones).

The product of its (nonzero) digits is 17496, while the sum is 36.

The square root of 666099 is about 816.1488834765. The cubic root of 666099 is about 87.3332443071. Note that the first 3 decimals are identical.

The spelling of 666099 in words is "six hundred sixty-six thousand, ninety-nine".