999999888666665 has 8 divisors (see below), whose sum is σ = 1270588093835400. Its totient is φ = 752941092643072.

The previous prime is 999999888666637. The next prime is 999999888666673. The reversal of 999999888666665 is 566666888999999.

It can be written as a sum of positive squares in 4 ways, for example, as 129822575148841 + 870177313517824 = 11393971^2 + 29498768^2 .

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 999999888666665 - 2⁶ = 999999888666601 is a prime.

It is a super-2 number, since 2×999999888666665² (a number of 31 digits) contains 22 as substring.

It is a nialpdrome in base 10.

It is a self number, because there is not a number n which added to its sum of digits gives 999999888666665.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 5882352286190 + ... + 5882352286359.

It is an arithmetic number, because the mean of its divisors is an integer number (158823511729425).

Almost surely, 2^{999999888666665} is an apocalyptic number.

It is an amenable number.

999999888666665 is a deficient number, since it is larger than the sum of its proper divisors (270588205168735).

999999888666665 is a wasteful number, since it uses less digits than its factorization.

999999888666665 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 11764704572571.

The product of its digits is 10579162152960, while the sum is 113.

The spelling of 999999888666665 in words is "nine hundred ninety-nine trillion, nine hundred ninety-nine billion, eight hundred eighty-eight million, six hundred sixty-six thousand, six hundred sixty-five".