491591278800 has 480 divisors, whose sum is σ = 1844381952000. Its totient is φ = 124016832000.

The previous prime is 491591278793. The next prime is 491591278847. The reversal of 491591278800 is 8872195194.

It is a happy number.

491591278800 is a `hidden beast` number, since 49 + 1 + 591 + 2 + 7 + 8 + 8 + 0 + 0 = 666.

It is a Harshad number since it is a multiple of its sum of digits (54).

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 95 ways as a sum of consecutive naturals, for example, 209097625 + ... + 209099975.

It is an arithmetic number, because the mean of its divisors is an integer number (3842462400).

Almost surely, 2^491591278800 is an apocalyptic number.

491591278800 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 491591278800, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (922190976000).

491591278800 is an abundant number, since it is smaller than the sum of its proper divisors (1352790673200).

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

491591278800 is a wasteful number, since it uses less digits than its factorization.

491591278800 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3416 (or 3399 counting only the distinct ones).

The product of its (nonzero) digits is 1451520, while the sum is 54.

The spelling of 491591278800 in words is "four hundred ninety-one billion, five hundred ninety-one million, two hundred seventy-eight thousand, eight hundred".