66508889 has 2 divisors, whose sum is σ = 66508890. Its totient is φ = 66508888.

The previous prime is 66508877. The next prime is 66508891. The reversal of 66508889 is 98880566.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 51724864 + 14784025 = 7192^2 + 3845^2 .

It is a cyclic number.

It is not a de Polignac number, because 66508889 - 2⁸ = 66508633 is a prime.

Together with 66508891, it forms a pair of twin primes.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (66508489) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 33254444 + 33254445.

It is an arithmetic number, because the mean of its divisors is an integer number (33254445).

Almost surely, 2^66508889 is an apocalyptic number.

It is an amenable number.

66508889 is a deficient number, since it is larger than the sum of its proper divisors (1).

66508889 is an equidigital number, since it uses as much as digits as its factorization.

66508889 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 829440, while the sum is 50.

The square root of 66508889 is about 8155.2982164971. The cubic root of 66508889 is about 405.1600018111.

The spelling of 66508889 in words is "sixty-six million, five hundred eight thousand, eight hundred eighty-nine".