66561053249 has 2 divisors, whose sum is σ = 66561053250. Its totient is φ = 66561053248.

The previous prime is 66561053231. The next prime is 66561053359. The reversal of 66561053249 is 94235016566.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 64576974400 + 1984078849 = 254120^2 + 44543^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-66561053249 is a prime.

It is not a weakly prime, because it can be changed into another prime (66561059249) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 33280526624 + 33280526625.

It is an arithmetic number, because the mean of its divisors is an integer number (33280526625).

Almost surely, 2^66561053249 is an apocalyptic number.

It is an amenable number.

66561053249 is a deficient number, since it is larger than the sum of its proper divisors (1).

66561053249 is an equidigital number, since it uses as much as digits as its factorization.

66561053249 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 1166400, while the sum is 47.

The spelling of 66561053249 in words is "sixty-six billion, five hundred sixty-one million, fifty-three thousand, two hundred forty-nine".