66138187 has 2 divisors, whose sum is σ = 66138188. Its totient is φ = 66138186.

The previous prime is 66138181. The next prime is 66138197. The reversal of 66138187 is 78183166.

66138187 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 66138187 - 2¹⁵ = 66105419 is a prime.

It is not a weakly prime, because it can be changed into another prime (66138181) 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 as a sum of consecutive naturals, namely, 33069093 + 33069094.

It is an arithmetic number, because the mean of its divisors is an integer number (33069094).

Almost surely, 2^66138187 is an apocalyptic number.

66138187 is a deficient number, since it is larger than the sum of its proper divisors (1).

66138187 is an equidigital number, since it uses as much as digits as its factorization.

66138187 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 48384, while the sum is 40.

The square root of 66138187 is about 8132.5387794956. The cubic root of 66138187 is about 404.4058493044.

The spelling of 66138187 in words is "sixty-six million, one hundred thirty-eight thousand, one hundred eighty-seven".