66400189 has 2 divisors, whose sum is σ = 66400190. Its totient is φ = 66400188.

The previous prime is 66400183. The next prime is 66400247. The reversal of 66400189 is 98100466.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 37724164 + 28676025 = 6142^2 + 5355^2 .

It is a cyclic number.

It is not a de Polignac number, because 66400189 - 2⁵ = 66400157 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (66400183) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 33200094 + 33200095.

It is an arithmetic number, because the mean of its divisors is an integer number (33200095).

Almost surely, 2^66400189 is an apocalyptic number.

It is an amenable number.

66400189 is a deficient number, since it is larger than the sum of its proper divisors (1).

66400189 is an equidigital number, since it uses as much as digits as its factorization.

66400189 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 10368, while the sum is 34.

The square root of 66400189 is about 8148.6311120335. The cubic root of 66400189 is about 404.9391546047.

The spelling of 66400189 in words is "sixty-six million, four hundred thousand, one hundred eighty-nine".