999981660 has 24 divisors (see below), whose sum is σ = 2799948816. Its totient is φ = 266661760.

The previous prime is 999981659. The next prime is 999981713. The reversal of 999981660 is 66189999.

999981660 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a self number, because there is not a number n which added to its sum of digits gives 999981660.

It is a congruent number.

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, 8333121 + ... + 8333240.

It is an arithmetic number, because the mean of its divisors is an integer number (116664534).

Almost surely, 2^999981660 is an apocalyptic number.

It is an amenable number.

999981660 is an abundant number, since it is smaller than the sum of its proper divisors (1799967156).

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

999981660 is a wasteful number, since it uses less digits than its factorization.

999981660 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 16666373 (or 16666371 counting only the distinct ones).

The product of its (nonzero) digits is 1889568, while the sum is 57.

The square root of 999981660 is about 31622.4866194928. The cubic root of 999981660 is about 999.9938866293.

The spelling of 999981660 in words is "nine hundred ninety-nine million, nine hundred eighty-one thousand, six hundred sixty".