191086840 has 128 divisors (see below), whose sum is σ = 513216000. Its totient is φ = 62673408.

The previous prime is 191086823. The next prime is 191086843. The reversal of 191086840 is 48680191.

It is a happy number.

191086840 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a self number, because there is not a number n which added to its sum of digits gives 191086840.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (191086843) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 710226 + ... + 710494.

It is an arithmetic number, because the mean of its divisors is an integer number (4009500).

Almost surely, 2^191086840 is an apocalyptic number.

191086840 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 191086840, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (256608000).

191086840 is an abundant number, since it is smaller than the sum of its proper divisors (322129160).

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

191086840 is a wasteful number, since it uses less digits than its factorization.

191086840 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 389 (or 385 counting only the distinct ones).

The product of its (nonzero) digits is 13824, while the sum is 37.

The square root of 191086840 is about 13823.4163649946. The cubic root of 191086840 is about 575.9837878024.

The spelling of 191086840 in words is "one hundred ninety-one million, eighty-six thousand, eight hundred forty".