813666 has 16 divisors (see below), whose sum is σ = 1859904. Its totient is φ = 232464.

The previous prime is 813647. The next prime is 813677. The reversal of 813666 is 666318.

It is a Curzon number.

It is a plaindrome in base 15.

It is an inconsummate number, since it does not exist a number n which divided by its sum of digits gives 813666.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 9645 + ... + 9728.

It is an arithmetic number, because the mean of its divisors is an integer number (116244).

2⁸¹³⁶⁶⁶ is an apocalyptic number.

813666 is an abundant number, since it is smaller than the sum of its proper divisors (1046238).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

813666 is a wasteful number, since it uses less digits than its factorization.

813666 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 19385.

The product of its digits is 5184, while the sum is 30.

The square root of 813666 is about 902.0343674162. The cubic root of 813666 is about 93.3573945901.

The spelling of 813666 in words is "eight hundred thirteen thousand, six hundred sixty-six".