66645289 has 2 divisors, whose sum is σ = 66645290. Its totient is φ = 66645288.

The previous prime is 66645259. The next prime is 66645307. The reversal of 66645289 is 98254666.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 34609689 + 32035600 = 5883^2 + 5660^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-66645289 is a prime.

It is not a weakly prime, because it can be changed into another prime (66645259) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 33322644 + 33322645.

It is an arithmetic number, because the mean of its divisors is an integer number (33322645).

Almost surely, 2^66645289 is an apocalyptic number.

It is an amenable number.

66645289 is a deficient number, since it is larger than the sum of its proper divisors (1).

66645289 is an equidigital number, since it uses as much as digits as its factorization.

66645289 is an evil number, because the sum of its binary digits is even.

The product of its digits is 622080, while the sum is 46.

The square root of 66645289 is about 8163.6565949334. The cubic root of 66645289 is about 405.4367873091.

The spelling of 66645289 in words is "sixty-six million, six hundred forty-five thousand, two hundred eighty-nine".