99661566828097 has 16 divisors (see below), whose sum is σ = 103270802720400. Its totient is φ = 96063948207360.

The previous prime is 99661566828017. The next prime is 99661566828121. The reversal of 99661566828097 is 79082866516699.

It is a Cunningham number, because it is equal to 9983064²+1.

It can be written as a sum of positive squares in 8 ways, for example, as 31148186075136 + 68513380752961 = 5581056^2 + 8277281^2 .

It is a cyclic number.

It is not a de Polignac number, because 99661566828097 - 2¹¹ = 99661566826049 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 99661566828097.

It is not an unprimeable number, because it can be changed into a prime (99661566828017) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 50503663 + ... + 52439899.

It is an arithmetic number, because the mean of its divisors is an integer number (6454425170025).

Almost surely, 2^{99661566828097} is an apocalyptic number.

It is an amenable number.

99661566828097 is a deficient number, since it is larger than the sum of its proper divisors (3609235892303).

99661566828097 is a wasteful number, since it uses less digits than its factorization.

99661566828097 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1939236.

The product of its (nonzero) digits is 4232632320, while the sum is 82.

The spelling of 99661566828097 in words is "ninety-nine trillion, six hundred sixty-one billion, five hundred sixty-six million, eight hundred twenty-eight thousand, ninety-seven".