1666744189 has 4 divisors (see below), whose sum is σ = 1818266400. Its totient is φ = 1515221980.

The previous prime is 1666744169. The next prime is 1666744229. The reversal of 1666744189 is 9814476661.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 1666744189 - 2⁹ = 1666743677 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1666744139) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 75761089 + ... + 75761110.

It is an arithmetic number, because the mean of its divisors is an integer number (454566600).

Almost surely, 2^1666744189 is an apocalyptic number.

It is an amenable number.

1666744189 is a deficient number, since it is larger than the sum of its proper divisors (151522211).

1666744189 is a wasteful number, since it uses less digits than its factorization.

1666744189 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 151522210.

The product of its digits is 1741824, while the sum is 52.

The square root of 1666744189 is about 40825.7784861477. The cubic root of 1666744189 is about 1185.6494837896.

The spelling of 1666744189 in words is "one billion, six hundred sixty-six million, seven hundred forty-four thousand, one hundred eighty-nine".