66857279 has 2 divisors, whose sum is σ = 66857280. Its totient is φ = 66857278.

The previous prime is 66857227. The next prime is 66857293. The reversal of 66857279 is 97275866.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 66857279 - 2¹² = 66853183 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (66857299) 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, 33428639 + 33428640.

It is an arithmetic number, because the mean of its divisors is an integer number (33428640).

Almost surely, 2^66857279 is an apocalyptic number.

66857279 is a deficient number, since it is larger than the sum of its proper divisors (1).

66857279 is an equidigital number, since it uses as much as digits as its factorization.

66857279 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 1270080, while the sum is 50.

The square root of 66857279 is about 8176.6300515555. The cubic root of 66857279 is about 405.8662128852.

The spelling of 66857279 in words is "sixty-six million, eight hundred fifty-seven thousand, two hundred seventy-nine".