66564871 has 2 divisors, whose sum is σ = 66564872. Its totient is φ = 66564870.

The previous prime is 66564851. The next prime is 66564881. The reversal of 66564871 is 17846566.

It is a happy number.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 66564871 - 2²³ = 58176263 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (66564811) 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, 33282435 + 33282436.

It is an arithmetic number, because the mean of its divisors is an integer number (33282436).

Almost surely, 2^66564871 is an apocalyptic number.

66564871 is a deficient number, since it is larger than the sum of its proper divisors (1).

66564871 is an equidigital number, since it uses as much as digits as its factorization.

66564871 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 241920, while the sum is 43.

The square root of 66564871 is about 8158.7297418164. The cubic root of 66564871 is about 405.2736473035.

It can be divided in two parts, 665 and 64871, that added together give a 16-th power (65536 = 2¹⁶).

The spelling of 66564871 in words is "sixty-six million, five hundred sixty-four thousand, eight hundred seventy-one".