491806590 has 128 divisors (see below), whose sum is σ = 1352153088. Its totient is φ = 113402880.

The previous prime is 491806541. The next prime is 491806591. The reversal of 491806590 is 95608194.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (491806591) by changing a digit.

It is a polite number, since it can be written in 63 ways as a sum of consecutive naturals, for example, 573442 + ... + 574298.

It is an arithmetic number, because the mean of its divisors is an integer number (10563696).

Almost surely, 2^491806590 is an apocalyptic number.

It is a practical number, because each smaller number is the sum of distinct divisors of 491806590, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (676076544).

491806590 is an abundant number, since it is smaller than the sum of its proper divisors (860346498).

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

491806590 is a wasteful number, since it uses less digits than its factorization.

491806590 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 962.

The product of its (nonzero) digits is 77760, while the sum is 42.

The square root of 491806590 is about 22176.7127861638. The cubic root of 491806590 is about 789.3412176038.

The spelling of 491806590 in words is "four hundred ninety-one million, eight hundred six thousand, five hundred ninety".