66870191 has 2 divisors, whose sum is σ = 66870192. Its totient is φ = 66870190.

The previous prime is 66870179. The next prime is 66870217. The reversal of 66870191 is 19107866.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 66870191 - 2⁶ = 66870127 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (66870121) 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, 33435095 + 33435096.

It is an arithmetic number, because the mean of its divisors is an integer number (33435096).

Almost surely, 2^66870191 is an apocalyptic number.

66870191 is a deficient number, since it is larger than the sum of its proper divisors (1).

66870191 is an equidigital number, since it uses as much as digits as its factorization.

66870191 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 18144, while the sum is 38.

The square root of 66870191 is about 8177.4195807724. The cubic root of 66870191 is about 405.8923392212.

The spelling of 66870191 in words is "sixty-six million, eight hundred seventy thousand, one hundred ninety-one".