66388657 has 2 divisors, whose sum is σ = 66388658. Its totient is φ = 66388656.

The previous prime is 66388561. The next prime is 66388681. The reversal of 66388657 is 75688366.

It is a happy number.

66388657 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 44635761 + 21752896 = 6681^2 + 4664^2 .

It is a cyclic number.

It is not a de Polignac number, because 66388657 - 2¹⁹ = 65864369 is a prime.

It is a Chen prime.

It is a self number, because there is not a number n which added to its sum of digits gives 66388657.

It is not a weakly prime, because it can be changed into another prime (66388697) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 33194328 + 33194329.

It is an arithmetic number, because the mean of its divisors is an integer number (33194329).

Almost surely, 2^66388657 is an apocalyptic number.

It is an amenable number.

66388657 is a deficient number, since it is larger than the sum of its proper divisors (1).

66388657 is an equidigital number, since it uses as much as digits as its factorization.

66388657 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 1451520, while the sum is 49.

The square root of 66388657 is about 8147.9234777948. The cubic root of 66388657 is about 404.9157107523.

The spelling of 66388657 in words is "sixty-six million, three hundred eighty-eight thousand, six hundred fifty-seven".