66105011561 has 2 divisors, whose sum is σ = 66105011562. Its totient is φ = 66105011560.

The previous prime is 66105011501. The next prime is 66105011657. The reversal of 66105011561 is 16511050166.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 65779425625 + 325585936 = 256475^2 + 18044^2 .

It is a cyclic number.

It is not a de Polignac number, because 66105011561 - 2²² = 66100817257 is a prime.

It is not a weakly prime, because it can be changed into another prime (66105011501) 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, 33052505780 + 33052505781.

It is an arithmetic number, because the mean of its divisors is an integer number (33052505781).

Almost surely, 2^66105011561 is an apocalyptic number.

It is an amenable number.

66105011561 is a deficient number, since it is larger than the sum of its proper divisors (1).

66105011561 is an equidigital number, since it uses as much as digits as its factorization.

66105011561 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 5400, while the sum is 32.

The spelling of 66105011561 in words is "sixty-six billion, one hundred five million, eleven thousand, five hundred sixty-one".