66438896281 has 2 divisors, whose sum is σ = 66438896282. Its totient is φ = 66438896280.

The previous prime is 66438896243. The next prime is 66438896389. The reversal of 66438896281 is 18269883466.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 59397001225 + 7041895056 = 243715^2 + 83916^2 .

It is a cyclic number.

It is not a de Polignac number, because 66438896281 - 2²³ = 66430507673 is a prime.

It is a super-2 number, since 2×66438896281² (a number of 22 digits) contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (66438896221) 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, 33219448140 + 33219448141.

It is an arithmetic number, because the mean of its divisors is an integer number (33219448141).

Almost surely, 2^66438896281 is an apocalyptic number.

It is an amenable number.

66438896281 is a deficient number, since it is larger than the sum of its proper divisors (1).

66438896281 is an equidigital number, since it uses as much as digits as its factorization.

66438896281 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 23887872, while the sum is 61.

The spelling of 66438896281 in words is "sixty-six billion, four hundred thirty-eight million, eight hundred ninety-six thousand, two hundred eighty-one".