491371783680 has 160 divisors (see below), whose sum is σ = 1571636667744. Its totient is φ = 130967207936.

The previous prime is 491371783631. The next prime is 491371783681. The reversal of 491371783680 is 86387173194.

It is a happy number.

It is a tau number, because it is divible by the number of its divisors (160).

It is a self number, because there is not a number n which added to its sum of digits gives 491371783680.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (491371783681) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 16520182 + ... + 16549898.

Almost surely, 2^491371783680 is an apocalyptic number.

491371783680 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 491371783680, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (785818333872).

491371783680 is an abundant number, since it is smaller than the sum of its proper divisors (1080264884064).

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

491371783680 is a wasteful number, since it uses less digits than its factorization.

491371783680 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 31896 (or 31880 counting only the distinct ones).

The product of its (nonzero) digits is 6096384, while the sum is 57.

The spelling of 491371783680 in words is "four hundred ninety-one billion, three hundred seventy-one million, seven hundred eighty-three thousand, six hundred eighty".