813866 has 8 divisors (see below), whose sum is σ = 1226820. Its totient is φ = 404928.

The previous prime is 813863. The next prime is 813871. The reversal of 813866 is 668318.

813866 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It can be written as a sum of positive squares in 2 ways, for example, as 758641 + 55225 = 871^2 + 235^2 .

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

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 813866.

It is not an unprimeable number, because it can be changed into a prime (813863) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 431 + ... + 1346.

2⁸¹³⁸⁶⁶ is an apocalyptic number.

813866 is a deficient number, since it is larger than the sum of its proper divisors (412954).

813866 is a wasteful number, since it uses less digits than its factorization.

813866 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2008.

The product of its digits is 6912, while the sum is 32.

The square root of 813866 is about 902.1452211257. The cubic root of 813866 is about 93.3650430804.

The spelling of 813866 in words is "eight hundred thirteen thousand, eight hundred sixty-six".