66654881 has 2 divisors, whose sum is σ = 66654882. Its totient is φ = 66654880.

The previous prime is 66654857. The next prime is 66654911. The reversal of 66654881 is 18845666.

66654881 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 49224256 + 17430625 = 7016^2 + 4175^2 .

It is a cyclic number.

It is not a de Polignac number, because 66654881 - 2¹⁰ = 66653857 is a prime.

It is a super-3 number, since 3×66654881³ (a number of 24 digits) contains 333 as substring. Note that it is a super-d number also for d = 2.

It is a Sophie Germain prime.

It is a Curzon number.

It is not a weakly prime, because it can be changed into another prime (66614881) 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, 33327440 + 33327441.

It is an arithmetic number, because the mean of its divisors is an integer number (33327441).

Almost surely, 2^66654881 is an apocalyptic number.

It is an amenable number.

66654881 is a deficient number, since it is larger than the sum of its proper divisors (1).

66654881 is an equidigital number, since it uses as much as digits as its factorization.

66654881 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 276480, while the sum is 44.

The square root of 66654881 is about 8164.2440556367. The cubic root of 66654881 is about 405.4562373616.

The spelling of 66654881 in words is "sixty-six million, six hundred fifty-four thousand, eight hundred eighty-one".