20491851847680 has 960 divisors, whose sum is σ = 74796690608640. Its totient is φ = 5364817920000.

The previous prime is 20491851847679. The next prime is 20491851847703. The reversal of 20491851847680 is 8674815819402.

20491851847680 is a `hidden beast` number, since 2 + 0 + 4 + 9 + 1 + 85 + 1 + 8 + 476 + 80 = 666.

It is a tau number, because it is divible by the number of its divisors (960).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 79 ways as a sum of consecutive naturals, for example, 27286087305 + ... + 27286088055.

It is an arithmetic number, because the mean of its divisors is an integer number (77913219384).

Almost surely, 2^{20491851847680} is an apocalyptic number.

20491851847680 is a gapful number since it is divisible by the number (20) 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 20491851847680, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (37398345304320).

20491851847680 is an abundant number, since it is smaller than the sum of its proper divisors (54304838760960).

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

20491851847680 is an equidigital number, since it uses as much as digits as its factorization.

20491851847680 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1348 (or 1319 counting only the distinct ones).

The product of its (nonzero) digits is 30965760, while the sum is 63.

The spelling of 20491851847680 in words is "twenty trillion, four hundred ninety-one billion, eight hundred fifty-one million, eight hundred forty-seven thousand, six hundred eighty".