66078217 has 2 divisors, whose sum is σ = 66078218. Its totient is φ = 66078216.

The previous prime is 66078203. The next prime is 66078247. The reversal of 66078217 is 71287066.

It is a happy number.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 65593801 + 484416 = 8099^2 + 696^2 .

It is a cyclic number.

It is not a de Polignac number, because 66078217 - 2²³ = 57689609 is a prime.

It is not a weakly prime, because it can be changed into another prime (66078247) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 33039108 + 33039109.

It is an arithmetic number, because the mean of its divisors is an integer number (33039109).

Almost surely, 2^66078217 is an apocalyptic number.

It is an amenable number.

66078217 is a deficient number, since it is larger than the sum of its proper divisors (1).

66078217 is an equidigital number, since it uses as much as digits as its factorization.

66078217 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 28224, while the sum is 37.

The square root of 66078217 is about 8128.8509028029. The cubic root of 66078217 is about 404.2835823070.

The spelling of 66078217 in words is "sixty-six million, seventy-eight thousand, two hundred seventeen".