161988866 has 24 divisors (see below), whose sum is σ = 267604560. Its totient is φ = 73487856.

The previous prime is 161988847. The next prime is 161988887. The reversal of 161988866 is 668889161.

It is a happy number.

It is a Curzon number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 15881 + ... + 24003.

It is an arithmetic number, because the mean of its divisors is an integer number (11150190).

Almost surely, 2^161988866 is an apocalyptic number.

161988866 is a deficient number, since it is larger than the sum of its proper divisors (105615694).

161988866 is a wasteful number, since it uses less digits than its factorization.

161988866 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 8210 (or 8197 counting only the distinct ones).

The product of its digits is 995328, while the sum is 53.

The square root of 161988866 is about 12727.4846690145. The cubic root of 161988866 is about 545.1236887853.

The spelling of 161988866 in words is "one hundred sixty-one million, nine hundred eighty-eight thousand, eight hundred sixty-six".