66717257 has 2 divisors, whose sum is σ = 66717258. Its totient is φ = 66717256.

The previous prime is 66717251. The next prime is 66717263. The reversal of 66717257 is 75271766.

66717257 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a balanced prime because it is at equal distance from previous prime (66717251) and next prime (66717263).

It can be written as a sum of positive squares in only one way, i.e., 65674816 + 1042441 = 8104^2 + 1021^2 .

It is a cyclic number.

It is not a de Polignac number, because 66717257 - 2⁴ = 66717241 is a prime.

It is not a weakly prime, because it can be changed into another prime (66717251) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 33358628 + 33358629.

It is an arithmetic number, because the mean of its divisors is an integer number (33358629).

Almost surely, 2^66717257 is an apocalyptic number.

It is an amenable number.

66717257 is a deficient number, since it is larger than the sum of its proper divisors (1).

66717257 is an equidigital number, since it uses as much as digits as its factorization.

66717257 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 123480, while the sum is 41.

The square root of 66717257 is about 8168.0632343292. The cubic root of 66717257 is about 405.5826739801.

The spelling of 66717257 in words is "sixty-six million, seven hundred seventeen thousand, two hundred fifty-seven".