66320647 has 2 divisors, whose sum is σ = 66320648. Its totient is φ = 66320646.

The previous prime is 66320627. The next prime is 66320671. The reversal of 66320647 is 74602366.

It is a weak prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-66320647 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (66320627) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 33160323 + 33160324.

It is an arithmetic number, because the mean of its divisors is an integer number (33160324).

Almost surely, 2^66320647 is an apocalyptic number.

66320647 is a deficient number, since it is larger than the sum of its proper divisors (1).

66320647 is an equidigital number, since it uses as much as digits as its factorization.

66320647 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 36288, while the sum is 34.

The square root of 66320647 is about 8143.7489524174. The cubic root of 66320647 is about 404.7773953246. Note that the first 3 decimals are identical.

The spelling of 66320647 in words is "sixty-six million, three hundred twenty thousand, six hundred forty-seven".