66856859 has 2 divisors, whose sum is σ = 66856860. Its totient is φ = 66856858.

The previous prime is 66856847. The next prime is 66856871. The reversal of 66856859 is 95865866.

It is a happy number.

It is a balanced prime because it is at equal distance from previous prime (66856847) and next prime (66856871).

It is a cyclic number.

It is not a de Polignac number, because 66856859 - 2⁴ = 66856843 is a prime.

It is a super-3 number, since 3×66856859³ (a number of 24 digits) contains 333 as substring.

It is a Chen prime.

It is a self number, because there is not a number n which added to its sum of digits gives 66856859.

It is not a weakly prime, because it can be changed into another prime (66856819) 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, 33428429 + 33428430.

It is an arithmetic number, because the mean of its divisors is an integer number (33428430).

Almost surely, 2^66856859 is an apocalyptic number.

66856859 is a deficient number, since it is larger than the sum of its proper divisors (1).

66856859 is an equidigital number, since it uses as much as digits as its factorization.

66856859 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 3110400, while the sum is 53.

The square root of 66856859 is about 8176.6043685628. The cubic root of 66856859 is about 405.8653629943.

The spelling of 66856859 in words is "sixty-six million, eight hundred fifty-six thousand, eight hundred fifty-nine".