1989166 has 4 divisors (see below), whose sum is σ = 2983752. Its totient is φ = 994582.

The previous prime is 1989161. The next prime is 1989193. The reversal of 1989166 is 6619891.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 6619891 = 2293 ⋅2887.

It is a Smith number, since the sum of its digits (40) coincides with the sum of the digits of its prime factors. Since it is squarefree, it is also a hoax number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1989161) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 497290 + ... + 497293.

It is an arithmetic number, because the mean of its divisors is an integer number (745938).

2^1989166 is an apocalyptic number.

1989166 is a deficient number, since it is larger than the sum of its proper divisors (994586).

1989166 is an equidigital number, since it uses as much as digits as its factorization.

1989166 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 994585.

The product of its digits is 23328, while the sum is 40.

The square root of 1989166 is about 1410.3779635261. The cubic root of 1989166 is about 125.7641932158.

The spelling of 1989166 in words is "one million, nine hundred eighty-nine thousand, one hundred sixty-six".