66408893 has 2 divisors, whose sum is σ = 66408894. Its totient is φ = 66408892.

The previous prime is 66408877. The next prime is 66408907. The reversal of 66408893 is 39880466.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 57486724 + 8922169 = 7582^2 + 2987^2 .

It is a cyclic number.

It is not a de Polignac number, because 66408893 - 2⁴ = 66408877 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (66408193) 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, 33204446 + 33204447.

It is an arithmetic number, because the mean of its divisors is an integer number (33204447).

Almost surely, 2^66408893 is an apocalyptic number.

It is an amenable number.

66408893 is a deficient number, since it is larger than the sum of its proper divisors (1).

66408893 is an equidigital number, since it uses as much as digits as its factorization.

66408893 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 248832, while the sum is 44.

The square root of 66408893 is about 8149.1651719670. The cubic root of 66408893 is about 404.9568475082.

Multiplying 66408893 by its sum of digits (44), we get a palindrome (2921991292).

The spelling of 66408893 in words is "sixty-six million, four hundred eight thousand, eight hundred ninety-three".