491191680 has 384 divisors, whose sum is σ = 1908852480. Its totient is φ = 106917888.

The previous prime is 491191639. The next prime is 491191681. The reversal of 491191680 is 86191194.

It is a tau number, because it is divible by the number of its divisors (384).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (491191681) by changing a digit.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 2163727 + ... + 2163953.

It is an arithmetic number, because the mean of its divisors is an integer number (4970970).

Almost surely, 2^491191680 is an apocalyptic number.

491191680 is a gapful number since it is divisible by the number (40) 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 491191680, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (954426240).

491191680 is an abundant number, since it is smaller than the sum of its proper divisors (1417660800).

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

491191680 is a wasteful number, since it uses less digits than its factorization.

491191680 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 286 (or 267 counting only the distinct ones).

The product of its (nonzero) digits is 15552, while the sum is 39.

The square root of 491191680 is about 22162.8445827696. The cubic root of 491191680 is about 789.0121070363.

The spelling of 491191680 in words is "four hundred ninety-one million, one hundred ninety-one thousand, six hundred eighty".