173989666 has 4 divisors (see below), whose sum is σ = 260984502. Its totient is φ = 86994832.

The previous prime is 173989657. The next prime is 173989667. The reversal of 173989666 is 666989371.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 666989371 = 16067 ⋅41513.

It can be written as a sum of positive squares in only one way, i.e., 150185025 + 23804641 = 12255^2 + 4879^2 .

It is not an unprimeable number, because it can be changed into a prime (173989667) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 43497415 + ... + 43497418.

Almost surely, 2^173989666 is an apocalyptic number.

173989666 is a deficient number, since it is larger than the sum of its proper divisors (86994836).

173989666 is an equidigital number, since it uses as much as digits as its factorization.

173989666 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 86994835.

The product of its digits is 2939328, while the sum is 55.

The square root of 173989666 is about 13190.5142431976. The cubic root of 173989666 is about 558.2659647733.

The spelling of 173989666 in words is "one hundred seventy-three million, nine hundred eighty-nine thousand, six hundred sixty-six".