999966111996666 has 32 divisors (see below), whose sum is σ = 2010235849973568. Its totient is φ = 331608709555200.

The previous prime is 999966111996653. The next prime is 999966111996667. The reversal of 999966111996666 is 666699111669999.

999966111996666 is a strobogrammatic number because it is the same when read upside-down.

It is a zygodrome in base 10.

It is a self number, because there is not a number n which added to its sum of digits gives 999966111996666.

It is not an unprimeable number, because it can be changed into a prime (999966111996667) 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, 491887660 + ... + 493916391.

It is an arithmetic number, because the mean of its divisors is an integer number (62819870311674).

Almost surely, 2^{999966111996666} is an apocalyptic number.

999966111996666 is an abundant number, since it is smaller than the sum of its proper divisors (1010269737976902).

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

999966111996666 is a wasteful number, since it uses less digits than its factorization.

999966111996666 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 985804926.

The product of its digits is 24794911296, while the sum is 93.

The spelling of 999966111996666 in words is "nine hundred ninety-nine trillion, nine hundred sixty-six billion, one hundred eleven million, nine hundred ninety-six thousand, six hundred sixty-six".