1666011173 has 4 divisors (see below), whose sum is σ = 1711038540. Its totient is φ = 1620983808.

The previous prime is 1666011163. The next prime is 1666011211. The reversal of 1666011173 is 3711106661.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 3711106661 = 2399 ⋅1546939.

It can be written as a sum of positive squares in 2 ways, for example, as 1577519524 + 88491649 = 39718^2 + 9407^2 .

It is a cyclic number.

It is not a de Polignac number, because 1666011173 - 2⁴ = 1666011157 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 (1666011133) 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 3 ways as a sum of consecutive naturals, for example, 22513628 + ... + 22513701.

It is an arithmetic number, because the mean of its divisors is an integer number (427759635).

Almost surely, 2^1666011173 is an apocalyptic number.

It is an amenable number.

1666011173 is a deficient number, since it is larger than the sum of its proper divisors (45027367).

1666011173 is an equidigital number, since it uses as much as digits as its factorization.

1666011173 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 45027366.

The product of its (nonzero) digits is 4536, while the sum is 32.

The square root of 1666011173 is about 40816.8001318085. The cubic root of 1666011173 is about 1185.4756463793.

The spelling of 1666011173 in words is "one billion, six hundred sixty-six million, eleven thousand, one hundred seventy-three".