99660109306781 has 2 divisors, whose sum is σ = 99660109306782. Its totient is φ = 99660109306780.

The previous prime is 99660109306727. The next prime is 99660109306801. The reversal of 99660109306781 is 18760390106699.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 55823924914681 + 43836184392100 = 7471541^2 + 6620890^2 .

It is an emirp because it is prime and its reverse (18760390106699) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 99660109306781 - 2⁶ = 99660109306717 is a prime.

It is a super-2 number, since 2×99660109306781² (a number of 29 digits) contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (99660109300781) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (29) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 49830054653390 + 49830054653391.

It is an arithmetic number, because the mean of its divisors is an integer number (49830054653391).

Almost surely, 2^{99660109306781} is an apocalyptic number.

It is an amenable number.

99660109306781 is a deficient number, since it is larger than the sum of its proper divisors (1).

99660109306781 is an equidigital number, since it uses as much as digits as its factorization.

99660109306781 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 26453952, while the sum is 65.

The spelling of 99660109306781 in words is "ninety-nine trillion, six hundred sixty billion, one hundred nine million, three hundred six thousand, seven hundred eighty-one".