891666 has 12 divisors (see below), whose sum is σ = 1931982. Its totient is φ = 297216.

The previous prime is 891661. The next prime is 891677. The reversal of 891666 is 666198.

891666 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 only one way, i.e., 772641 + 119025 = 879^2 + 345^2 .

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

It is a Curzon number.

It is a self number, because there is not a number n which added to its sum of digits gives 891666.

It is an inconsummate number, since it does not exist a number n which divided by its sum of digits gives 891666.

It is not an unprimeable number, because it can be changed into a prime (891661) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 24751 + ... + 24786.

2⁸⁹¹⁶⁶⁶ is an apocalyptic number.

891666 is an abundant number, since it is smaller than the sum of its proper divisors (1040316).

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

891666 is a wasteful number, since it uses less digits than its factorization.

891666 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 49545 (or 49542 counting only the distinct ones).

The product of its digits is 15552, while the sum is 36.

The square root of 891666 is about 944.2806786120. The cubic root of 891666 is about 96.2499994378.

The spelling of 891666 in words is "eight hundred ninety-one thousand, six hundred sixty-six".