191889920 has 80 divisors (see below), whose sum is σ = 480237120. Its totient is φ = 73396224.

The previous prime is 191889883. The next prime is 191889961. The reversal of 191889920 is 29988191.

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

It is a Smith number, since the sum of its digits (47) coincides with the sum of the digits of its prime factors.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (7) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 57251 + ... + 60509.

It is an arithmetic number, because the mean of its divisors is an integer number (6002964).

Almost surely, 2^191889920 is an apocalyptic number.

191889920 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 191889920, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (240118560).

191889920 is an abundant number, since it is smaller than the sum of its proper divisors (288347200).

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

191889920 is an equidigital number, since it uses as much as digits as its factorization.

191889920 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3305 (or 3289 counting only the distinct ones).

The product of its (nonzero) digits is 93312, while the sum is 47.

The square root of 191889920 is about 13852.4337211914. The cubic root of 191889920 is about 576.7895550787.

The spelling of 191889920 in words is "one hundred ninety-one million, eight hundred eighty-nine thousand, nine hundred twenty".