9891666 has 64 divisors (see below), whose sum is σ = 23961600. Its totient is φ = 3013200.

The previous prime is 9891653. The next prime is 9891689. The reversal of 9891666 is 6661989.

It is an unprimeable number.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 31651 + ... + 31961.

It is an arithmetic number, because the mean of its divisors is an integer number (374400).

Almost surely, 2^9891666 is an apocalyptic number.

It is a practical number, because each smaller number is the sum of distinct divisors of 9891666, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (11980800).

9891666 is an abundant number, since it is smaller than the sum of its proper divisors (14069934).

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

9891666 is a wasteful number, since it uses less digits than its factorization.

9891666 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 372 (or 366 counting only the distinct ones).

The product of its digits is 139968, while the sum is 45.

The square root of 9891666 is about 3145.1019061391. The cubic root of 9891666 is about 214.6626474349.

The spelling of 9891666 in words is "nine million, eight hundred ninety-one thousand, six hundred sixty-six".