191139840 has 312 divisors, whose sum is σ = 713010168. Its totient is φ = 47185920.

The previous prime is 191139803. The next prime is 191139863. The reversal of 191139840 is 48931191.

It can be written as a sum of positive squares in 4 ways, for example, as 5308416 + 185831424 = 2304^2 + 13632^2 .

It is a Harshad number since it is a multiple of its sum of digits (36).

It is a junction number, because it is equal to n+sod(n) for n = 191139795 and 191139804.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 3133410 + ... + 3133470.

It is an arithmetic number, because the mean of its divisors is an integer number (2285289).

Almost surely, 2^191139840 is an apocalyptic number.

191139840 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 191139840, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (356505084).

191139840 is an abundant number, since it is smaller than the sum of its proper divisors (521870328).

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

191139840 is a wasteful number, since it uses less digits than its factorization.

191139840 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 113 (or 88 counting only the distinct ones).

The product of its (nonzero) digits is 7776, while the sum is 36.

The square root of 191139840 is about 13825.3332690391. Note that the first 3 decimals coincide. The cubic root of 191139840 is about 576.0370346558.

The spelling of 191139840 in words is "one hundred ninety-one million, one hundred thirty-nine thousand, eight hundred forty".