66408917 has 2 divisors, whose sum is σ = 66408918. Its totient is φ = 66408916.

The previous prime is 66408907. The next prime is 66408949. The reversal of 66408917 is 71980466.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 65141041 + 1267876 = 8071^2 + 1126^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-66408917 is a prime.

It is a super-2 number, since 2×66408917² = 8820288514225778, which contains 22 as substring.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (66408907) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 33204458 + 33204459.

It is an arithmetic number, because the mean of its divisors is an integer number (33204459).

Almost surely, 2^66408917 is an apocalyptic number.

It is an amenable number.

66408917 is a deficient number, since it is larger than the sum of its proper divisors (1).

66408917 is an equidigital number, since it uses as much as digits as its factorization.

66408917 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 72576, while the sum is 41.

The square root of 66408917 is about 8149.1666445103. The cubic root of 66408917 is about 404.9568962916.

The spelling of 66408917 in words is "sixty-six million, four hundred eight thousand, nine hundred seventeen".