9999988866666 has 24 divisors (see below), whose sum is σ = 21666705399300. Its totient is φ = 3333319952256.

The previous prime is 9999988866631. The next prime is 9999988866667. The reversal of 9999988866666 is 6666688899999.

It can be written as a sum of positive squares in 2 ways, for example, as 9976343346225 + 23645520441 = 3158535^2 + 153771^2 .

It is a super-2 number, since 2×9999988866666² (a number of 27 digits) contains 22 as substring.

9999988866666 is a strobogrammatic number because it is the same when read upside-down.

It is a nialpdrome in base 10.

It is a zygodrome in base 10.

It is not an unprimeable number, because it can be changed into a prime (9999988866667) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 8435826 + ... + 9547938.

Almost surely, 2^{9999988866666} is an apocalyptic number.

9999988866666 is an abundant number, since it is smaller than the sum of its proper divisors (11666716532634).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

9999988866666 is a wasteful number, since it uses less digits than its factorization.

9999988866666 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1611670 (or 1611667 counting only the distinct ones).

The product of its digits is 235092492288, while the sum is 99.

The spelling of 9999988866666 in words is "nine trillion, nine hundred ninety-nine billion, nine hundred eighty-eight million, eight hundred sixty-six thousand, six hundred sixty-six".