66516889 has 2 divisors, whose sum is σ = 66516890. Its totient is φ = 66516888.

The previous prime is 66516839. The next prime is 66516899. The reversal of 66516889 is 98861566.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 66015625 + 501264 = 8125^2 + 708^2 .

It is a cyclic number.

It is not a de Polignac number, because 66516889 - 2¹⁷ = 66385817 is a prime.

It is not a weakly prime, because it can be changed into another prime (66516839) 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, 33258444 + 33258445.

It is an arithmetic number, because the mean of its divisors is an integer number (33258445).

Almost surely, 2^66516889 is an apocalyptic number.

It is an amenable number.

66516889 is a deficient number, since it is larger than the sum of its proper divisors (1).

66516889 is an equidigital number, since it uses as much as digits as its factorization.

66516889 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 622080, while the sum is 49.

The square root of 66516889 is about 8155.7886804404. The cubic root of 66516889 is about 405.1762460060.

The spelling of 66516889 in words is "sixty-six million, five hundred sixteen thousand, eight hundred eighty-nine".