191681928 has 96 divisors (see below), whose sum is σ = 540284160. Its totient is φ = 61326720.

The previous prime is 191681927. The next prime is 191681957. The reversal of 191681928 is 829186191.

191681928 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a Smith number, since the sum of its digits (45) coincides with the sum of the digits of its prime factors.

It is a nude number because it is divisible by every one of its digits.

It is not an unprimeable number, because it can be changed into a prime (191681921) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 350151 + ... + 350697.

It is an arithmetic number, because the mean of its divisors is an integer number (5627960).

Almost surely, 2^191681928 is an apocalyptic number.

191681928 is a gapful number since it is divisible by the number (18) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 191681928, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (270142080).

191681928 is an abundant number, since it is smaller than the sum of its proper divisors (348602232).

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

191681928 is a wasteful number, since it uses less digits than its factorization.

191681928 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 747 (or 740 counting only the distinct ones).

The product of its digits is 62208, while the sum is 45.

The square root of 191681928 is about 13844.9242684819. The cubic root of 191681928 is about 576.5810831519.

The spelling of 191681928 in words is "one hundred ninety-one million, six hundred eighty-one thousand, nine hundred twenty-eight".