66439871 has 2 divisors, whose sum is σ = 66439872. Its totient is φ = 66439870.

The previous prime is 66439861. The next prime is 66439873. The reversal of 66439871 is 17893466.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 66439871 - 2¹⁰ = 66438847 is a prime.

Together with 66439873, it forms a pair of twin primes.

It is a Chen prime.

It is a zygodrome in base 3.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (66439873) 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, 33219935 + 33219936.

It is an arithmetic number, because the mean of its divisors is an integer number (33219936).

Almost surely, 2^66439871 is an apocalyptic number.

66439871 is a deficient number, since it is larger than the sum of its proper divisors (1).

66439871 is an equidigital number, since it uses as much as digits as its factorization.

66439871 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 217728, while the sum is 44.

The square root of 66439871 is about 8151.0656358540. The cubic root of 66439871 is about 405.0198049554.

The spelling of 66439871 in words is "sixty-six million, four hundred thirty-nine thousand, eight hundred seventy-one".