981666 has 64 divisors (see below), whose sum is σ = 2592000. Its totient is φ = 275184.

The previous prime is 981653. The next prime is 981683. The reversal of 981666 is 666189.

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 981666.

It is an inconsummate number, since it does not exist a number n which divided by its sum of digits gives 981666.

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, 18496 + ... + 18548.

It is an arithmetic number, because the mean of its divisors is an integer number (40500).

2⁹⁸¹⁶⁶⁶ is an apocalyptic number.

It is a practical number, because each smaller number is the sum of distinct divisors of 981666, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1296000).

981666 is an abundant number, since it is smaller than the sum of its proper divisors (1610334).

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

981666 is a wasteful number, since it uses less digits than its factorization.

981666 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 85 (or 65 counting only the distinct ones).

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

The square root of 981666 is about 990.7905934152. The cubic root of 981666 is about 99.3850933144.

It can be divided in two parts, 98 and 1666, that added together give a square (1764 = 42²).

The spelling of 981666 in words is "nine hundred eighty-one thousand, six hundred sixty-six".