191855920 has 80 divisors (see below), whose sum is σ = 474121440. Its totient is φ = 71995392.

The previous prime is 191855887. The next prime is 191855921. The reversal of 191855920 is 29558191.

It is a tau number, because it is divible by the number of its divisors (80).

It is a Harshad number since it is a multiple of its sum of digits (40).

It is not an unprimeable number, because it can be changed into a prime (191855921) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 171202 + ... + 172318.

It is an arithmetic number, because the mean of its divisors is an integer number (5926518).

Almost surely, 2^191855920 is an apocalyptic number.

191855920 is a gapful number since it is divisible by the number (10) 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 191855920, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (237060720).

191855920 is an abundant number, since it is smaller than the sum of its proper divisors (282265520).

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

191855920 is a wasteful number, since it uses less digits than its factorization.

191855920 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1262 (or 1256 counting only the distinct ones).

The product of its (nonzero) digits is 32400, while the sum is 40.

The square root of 191855920 is about 13851.2064456494. The cubic root of 191855920 is about 576.7554869296.

The spelling of 191855920 in words is "one hundred ninety-one million, eight hundred fifty-five thousand, nine hundred twenty".