66188189 has 4 divisors (see below), whose sum is σ = 66268860. Its totient is φ = 66107520.

The previous prime is 66188183. The next prime is 66188197. The reversal of 66188189 is 98188166.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 98188166 = 2 ⋅49094083.

It can be written as a sum of positive squares in 2 ways, for example, as 42471289 + 23716900 = 6517^2 + 4870^2 .

It is a cyclic number.

It is not a de Polignac number, because 66188189 - 2¹² = 66184093 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 (66188183) 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, 39092 + ... + 40749.

It is an arithmetic number, because the mean of its divisors is an integer number (16567215).

Almost surely, 2^66188189 is an apocalyptic number.

It is an amenable number.

66188189 is a deficient number, since it is larger than the sum of its proper divisors (80671).

66188189 is an equidigital number, since it uses as much as digits as its factorization.

66188189 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 80670.

The product of its digits is 165888, while the sum is 47.

The square root of 66188189 is about 8135.6123924386. The cubic root of 66188189 is about 404.5077370259.

The spelling of 66188189 in words is "sixty-six million, one hundred eighty-eight thousand, one hundred eighty-nine".