21152566955520 has 4480 divisors, whose sum is σ = 104232738677760. Its totient is φ = 3996679864320.

The previous prime is 21152566955501. The next prime is 21152566955543. The reversal of 21152566955520 is 2555966525112.

21152566955520 is a `hidden beast` number, since 2 + 1 + 1 + 5 + 2 + 5 + 6 + 69 + 55 + 520 = 666.

It is a tau number, because it is divible by the number of its divisors (4480).

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 (23) of ones.

It is a polite number, since it can be written in 447 ways as a sum of consecutive naturals, for example, 315709954527 + ... + 315709954593.

It is an arithmetic number, because the mean of its divisors is an integer number (23266236312).

Almost surely, 2^{21152566955520} is an apocalyptic number.

21152566955520 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 21152566955520, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (52116369338880).

21152566955520 is an abundant number, since it is smaller than the sum of its proper divisors (83080171722240).

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

21152566955520 is an frugal number, since it uses more digits than its factorization.

21152566955520 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 165 (or 108 counting only the distinct ones).

The product of its (nonzero) digits is 8100000, while the sum is 54.

The spelling of 21152566955520 in words is "twenty-one trillion, one hundred fifty-two billion, five hundred sixty-six million, nine hundred fifty-five thousand, five hundred twenty".