191320866 has 80 divisors (see below), whose sum is σ = 472747968. Its totient is φ = 57348000.

The previous prime is 191320849. The next prime is 191320901. The reversal of 191320866 is 668023191.

191320866 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a zygodrome in base 3.

It is a self number, because there is not a number n which added to its sum of digits gives 191320866.

It is an unprimeable number.

It is a polite number, since it can be written in 39 ways as a sum of consecutive naturals, for example, 179451 + ... + 180513.

Almost surely, 2^191320866 is an apocalyptic number.

It is a practical number, because each smaller number is the sum of distinct divisors of 191320866, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (236373984).

191320866 is an abundant number, since it is smaller than the sum of its proper divisors (281427102).

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

191320866 is a wasteful number, since it uses less digits than its factorization.

191320866 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1189 (or 1180 counting only the distinct ones).

The product of its (nonzero) digits is 15552, while the sum is 36.

The square root of 191320866 is about 13831.8786142736. The cubic root of 191320866 is about 576.2188296138.

The spelling of 191320866 in words is "one hundred ninety-one million, three hundred twenty thousand, eight hundred sixty-six".