1980666 has 32 divisors (see below), whose sum is σ = 4509120. Its totient is φ = 644112.

The previous prime is 1980661. The next prime is 1980673. The reversal of 1980666 is 6660891.

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 1980666.

It is not an unprimeable number, because it can be changed into a prime (1980661) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 1896 + ... + 2748.

It is an arithmetic number, because the mean of its divisors is an integer number (140910).

2^1980666 is an apocalyptic number.

It is a practical number, because each smaller number is the sum of distinct divisors of 1980666, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (2254560).

1980666 is an abundant number, since it is smaller than the sum of its proper divisors (2528454).

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

1980666 is a wasteful number, since it uses less digits than its factorization.

1980666 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 907 (or 901 counting only the distinct ones).

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

The square root of 1980666 is about 1407.3613608452. The cubic root of 1980666 is about 125.5848011278.

The spelling of 1980666 in words is "one million, nine hundred eighty thousand, six hundred sixty-six".