818666 has 4 divisors (see below), whose sum is σ = 1228002. Its totient is φ = 409332.

The previous prime is 818659. The next prime is 818683. The reversal of 818666 is 666818.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in only one way, i.e., 758641 + 60025 = 871^2 + 245^2 .

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 204665 + ... + 204668.

2⁸¹⁸⁶⁶⁶ is an apocalyptic number.

818666 is a deficient number, since it is larger than the sum of its proper divisors (409336).

818666 is a wasteful number, since it uses less digits than its factorization.

818666 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 409335.

The product of its digits is 13824, while the sum is 35.

The square root of 818666 is about 904.8016357191. The cubic root of 818666 is about 93.5482321427.

The spelling of 818666 in words is "eight hundred eighteen thousand, six hundred sixty-six".