66709757 has 2 divisors, whose sum is σ = 66709758. Its totient is φ = 66709756.

The previous prime is 66709723. The next prime is 66709759. The reversal of 66709757 is 75790766.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 42758521 + 23951236 = 6539^2 + 4894^2 .

It is a cyclic number.

It is not a de Polignac number, because 66709757 - 2²⁰ = 65661181 is a prime.

Together with 66709759, it forms a pair of twin primes.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (66709759) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 33354878 + 33354879.

It is an arithmetic number, because the mean of its divisors is an integer number (33354879).

Almost surely, 2^66709757 is an apocalyptic number.

It is an amenable number.

66709757 is a deficient number, since it is larger than the sum of its proper divisors (1).

66709757 is an equidigital number, since it uses as much as digits as its factorization.

66709757 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 555660, while the sum is 47.

The square root of 66709757 is about 8167.6041162632. The cubic root of 66709757 is about 405.5674755933.

The spelling of 66709757 in words is "sixty-six million, seven hundred nine thousand, seven hundred fifty-seven".