64661818884161 has 2 divisors, whose sum is σ = 64661818884162. Its totient is φ = 64661818884160.

The previous prime is 64661818884127. The next prime is 64661818884191. The reversal of 64661818884161 is 16148881816646.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 61221235360000 + 3440583524161 = 7824400^2 + 1854881^2 .

It is a cyclic number.

It is not a de Polignac number, because 64661818884161 - 2¹⁸ = 64661818622017 is a prime.

It is a super-2 number, since 2×64661818884161² (a number of 28 digits) contains 22 as substring.

It is a Sophie Germain prime.

It is a Curzon number.

It is a junction number, because it is equal to n+sod(n) for n = 64661818884091 and 64661818884100.

It is not a weakly prime, because it can be changed into another prime (64661818884191) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 32330909442080 + 32330909442081.

It is an arithmetic number, because the mean of its divisors is an integer number (32330909442081).

Almost surely, 2^{64661818884161} is an apocalyptic number.

It is an amenable number.

64661818884161 is a deficient number, since it is larger than the sum of its proper divisors (1).

64661818884161 is an equidigital number, since it uses as much as digits as its factorization.

64661818884161 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 84934656, while the sum is 68.

The spelling of 64661818884161 in words is "sixty-four trillion, six hundred sixty-one billion, eight hundred eighteen million, eight hundred eighty-four thousand, one hundred sixty-one".