491778194987520 has 2560 divisors, whose sum is σ = 2138074583040000. Its totient is φ = 104647798554624.

The previous prime is 491778194987507. The next prime is 491778194987557. The reversal of 491778194987520 is 25789491877194.

491778194987520 is a `hidden beast` number, since 4 + 9 + 1 + 7 + 7 + 8 + 1 + 9 + 4 + 9 + 87 + 520 = 666.

It is a tau number, because it is divible by the number of its divisors (2560).

It is a self number, because there is not a number n which added to its sum of digits gives 491778194987520.

It is an unprimeable number.

It is a polite number, since it can be written in 255 ways as a sum of consecutive naturals, for example, 166309837882 + ... + 166309840838.

It is an arithmetic number, because the mean of its divisors is an integer number (835185384000).

Almost surely, 2^{491778194987520} is an apocalyptic number.

491778194987520 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 491778194987520, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1069037291520000).

491778194987520 is an abundant number, since it is smaller than the sum of its proper divisors (1646296388052480).

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

491778194987520 is a wasteful number, since it uses less digits than its factorization.

491778194987520 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3323 (or 3301 counting only the distinct ones).

The product of its (nonzero) digits is 2560481280, while the sum is 81.

The spelling of 491778194987520 in words is "four hundred ninety-one trillion, seven hundred seventy-eight billion, one hundred ninety-four million, nine hundred eighty-seven thousand, five hundred twenty".