66728187 has 12 divisors (see below), whose sum is σ = 96510960. Its totient is φ = 44427408.

The previous prime is 66728177. The next prime is 66728231. The reversal of 66728187 is 78182766.

It is not a de Polignac number, because 66728187 - 2⁸ = 66727931 is a prime.

It is not an unprimeable number, because it can be changed into a prime (66728147) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 3133 + ... + 11969.

It is an arithmetic number, because the mean of its divisors is an integer number (8042580).

Almost surely, 2^66728187 is an apocalyptic number.

66728187 is a deficient number, since it is larger than the sum of its proper divisors (29782773).

66728187 is a wasteful number, since it uses less digits than its factorization.

66728187 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 9682 (or 9679 counting only the distinct ones).

The product of its digits is 225792, while the sum is 45.

The square root of 66728187 is about 8168.7322761858. The cubic root of 66728187 is about 405.6048210566.

The spelling of 66728187 in words is "sixty-six million, seven hundred twenty-eight thousand, one hundred eighty-seven".