66718257 has 8 divisors (see below), whose sum is σ = 89157600. Its totient is φ = 44378880.

The previous prime is 66718247. The next prime is 66718273. The reversal of 66718257 is 75281766.

66718257 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 66718257 - 2⁷ = 66718129 is a prime.

It is a Smith number, since the sum of its digits (42) coincides with the sum of the digits of its prime factors. Since it is squarefree, it is also a hoax number.

It is not an unprimeable number, because it can be changed into a prime (66718207) 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 in 7 ways as a sum of consecutive naturals, for example, 23419 + ... + 26112.

It is an arithmetic number, because the mean of its divisors is an integer number (11144700).

Almost surely, 2^66718257 is an apocalyptic number.

It is an amenable number.

66718257 is a deficient number, since it is larger than the sum of its proper divisors (22439343).

66718257 is a wasteful number, since it uses less digits than its factorization.

66718257 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 49983.

The product of its digits is 141120, while the sum is 42.

The square root of 66718257 is about 8168.1244481215. The cubic root of 66718257 is about 405.5847003457.

The spelling of 66718257 in words is "sixty-six million, seven hundred eighteen thousand, two hundred fifty-seven".