66101165561 has 2 divisors, whose sum is σ = 66101165562. Its totient is φ = 66101165560.

The previous prime is 66101165531. The next prime is 66101165563. The reversal of 66101165561 is 16556110166.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 62822916025 + 3278249536 = 250645^2 + 57256^2 .

It is a cyclic number.

It is not a de Polignac number, because 66101165561 - 2⁶ = 66101165497 is a prime.

Together with 66101165563, it forms a pair of twin primes.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (66101165563) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 33050582780 + 33050582781.

It is an arithmetic number, because the mean of its divisors is an integer number (33050582781).

Almost surely, 2^66101165561 is an apocalyptic number.

It is an amenable number.

66101165561 is a deficient number, since it is larger than the sum of its proper divisors (1).

66101165561 is an equidigital number, since it uses as much as digits as its factorization.

66101165561 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 32400, while the sum is 38.

The spelling of 66101165561 in words is "sixty-six billion, one hundred one million, one hundred sixty-five thousand, five hundred sixty-one".