66744857 has 2 divisors, whose sum is σ = 66744858. Its totient is φ = 66744856.

The previous prime is 66744851. The next prime is 66744859. The reversal of 66744857 is 75844766.

It is a happy number.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 47831056 + 18913801 = 6916^2 + 4349^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-66744857 is a prime.

Together with 66744859, it forms a pair of twin primes.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (66744851) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 33372428 + 33372429.

It is an arithmetic number, because the mean of its divisors is an integer number (33372429).

Almost surely, 2^66744857 is an apocalyptic number.

It is an amenable number.

66744857 is a deficient number, since it is larger than the sum of its proper divisors (1).

66744857 is an equidigital number, since it uses as much as digits as its factorization.

66744857 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 1128960, while the sum is 47.

The square root of 66744857 is about 8169.7525666326. The cubic root of 66744857 is about 405.6385942375.

Subtracting 66744857 from its reverse (75844766), we obtain a palindrome (9099909).

The spelling of 66744857 in words is "sixty-six million, seven hundred forty-four thousand, eight hundred fifty-seven".