99661566828095 has 32 divisors (see below), whose sum is σ = 127500255999360. Its totient is φ = 74523143577600.

The previous prime is 99661566828017. The next prime is 99661566828121. The reversal of 99661566828095 is 59082866516699.

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

It is not a de Polignac number, because 99661566828095 - 2²⁰ = 99661565779519 is a prime.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 48917009 + ... + 50913621.

It is an arithmetic number, because the mean of its divisors is an integer number (3984382999980).

Almost surely, 2^{99661566828095} is an apocalyptic number.

99661566828095 is a deficient number, since it is larger than the sum of its proper divisors (27838689171265).

99661566828095 is a wasteful number, since it uses less digits than its factorization.

99661566828095 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2000675.

The product of its (nonzero) digits is 3023308800, while the sum is 80.

The spelling of 99661566828095 in words is "ninety-nine trillion, six hundred sixty-one billion, five hundred sixty-six million, eight hundred twenty-eight thousand, ninety-five".