1989666 has 24 divisors (see below), whose sum is σ = 4927104. Its totient is φ = 568440.

The previous prime is 1989643. The next prime is 1989671. The reversal of 1989666 is 6669891.

It is an unprimeable number.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 7770 + ... + 8021.

It is an arithmetic number, because the mean of its divisors is an integer number (205296).

2^1989666 is an apocalyptic number.

1989666 is an abundant number, since it is smaller than the sum of its proper divisors (2937438).

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

1989666 is a wasteful number, since it uses less digits than its factorization.

1989666 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 15806 (or 15803 counting only the distinct ones).

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

The square root of 1989666 is about 1410.5552098376. Note that the first 3 decimals coincide. The cubic root of 1989666 is about 125.7747297637.

The spelling of 1989666 in words is "one million, nine hundred eighty-nine thousand, six hundred sixty-six".