999888111888666 has 512 divisors, whose sum is σ = 2853783810662400. Its totient is φ = 225123053137920.

The previous prime is 999888111888623. The next prime is 999888111888697. The reversal of 999888111888666 is 666888111888999.

999888111888666 is a strobogrammatic number because it is the same when read upside-down.

It is a zygodrome in base 10.

It is an unprimeable number.

It is a polite number, since it can be written in 255 ways as a sum of consecutive naturals, for example, 17290398240 + ... + 17290456068.

It is an arithmetic number, because the mean of its divisors is an integer number (5573796505200).

Almost surely, 2^{999888111888666} is an apocalyptic number.

It is a practical number, because each smaller number is the sum of distinct divisors of 999888111888666, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1426891905331200).

999888111888666 is an abundant number, since it is smaller than the sum of its proper divisors (1853895698773734).

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

999888111888666 is a wasteful number, since it uses less digits than its factorization.

999888111888666 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 60614.

The product of its digits is 41278242816, while the sum is 96.

The spelling of 999888111888666 in words is "nine hundred ninety-nine trillion, eight hundred eighty-eight billion, one hundred eleven million, eight hundred eighty-eight thousand, six hundred sixty-six".