21541520000 has 640 divisors, whose sum is σ = 72269366400. Its totient is φ = 6174720000.

The previous prime is 21541519939. The next prime is 21541520003. The reversal of 21541520000 is 2514512.

It is a tau number, because it is divible by the number of its divisors (640).

It is a Harshad number since it is a multiple of its sum of digits (20).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21541520003) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 79 ways as a sum of consecutive naturals, for example, 80079866 + ... + 80080134.

It is an arithmetic number, because the mean of its divisors is an integer number (112920885).

Almost surely, 2^21541520000 is an apocalyptic number.

21541520000 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 21541520000, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (36134683200).

21541520000 is an abundant number, since it is smaller than the sum of its proper divisors (50727846400).

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

21541520000 is a wasteful number, since it uses less digits than its factorization.

21541520000 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 334 (or 307 counting only the distinct ones).

The product of its (nonzero) digits is 400, while the sum is 20.

The spelling of 21541520000 in words is "twenty-one billion, five hundred forty-one million, five hundred twenty thousand".