66601009 has 2 divisors, whose sum is σ = 66601010. Its totient is φ = 66601008.

The previous prime is 66600991. The next prime is 66601027. The reversal of 66601009 is 90010666.

It is a happy number.

It is a balanced prime because it is at equal distance from previous prime (66600991) and next prime (66601027).

It can be written as a sum of positive squares in only one way, i.e., 66471409 + 129600 = 8153^2 + 360^2 .

It is a cyclic number.

It is not a de Polignac number, because 66601009 - 2⁵ = 66600977 is a prime.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (66601709) 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, 33300504 + 33300505.

It is an arithmetic number, because the mean of its divisors is an integer number (33300505).

Almost surely, 2^66601009 is an apocalyptic number.

It is an amenable number.

66601009 is a deficient number, since it is larger than the sum of its proper divisors (1).

66601009 is an equidigital number, since it uses as much as digits as its factorization.

66601009 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 1944, while the sum is 28.

The square root of 66601009 is about 8160.9441243033. The cubic root of 66601009 is about 405.3469749173.

The spelling of 66601009 in words is "sixty-six million, six hundred one thousand, nine".