21798555563520 has 1600 divisors, whose sum is σ = 84619564001280. Its totient is φ = 5345532444672.

The previous prime is 21798555563513. The next prime is 21798555563531. The reversal of 21798555563520 is 2536555589712.

21798555563520 is a `hidden beast` number, since 2 + 1 + 7 + 9 + 8 + 5 + 55 + 56 + 3 + 520 = 666.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 159 ways as a sum of consecutive naturals, for example, 37779125472 + ... + 37779126048.

Almost surely, 2^{21798555563520} is an apocalyptic number.

21798555563520 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 21798555563520, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (42309782000640).

21798555563520 is an abundant number, since it is smaller than the sum of its proper divisors (62821008437760).

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

21798555563520 is a wasteful number, since it uses less digits than its factorization.

21798555563520 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 897 (or 872 counting only the distinct ones).

The product of its (nonzero) digits is 113400000, while the sum is 63.

The spelling of 21798555563520 in words is "twenty-one trillion, seven hundred ninety-eight billion, five hundred fifty-five million, five hundred sixty-three thousand, five hundred twenty".