21525201280 has 256 divisors, whose sum is σ = 59089824000. Its totient is φ = 7425187840.

The previous prime is 21525201239. The next prime is 21525201281. The reversal of 21525201280 is 8210252512.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21525201281) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (7) of ones.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 12044547 + ... + 12046333.

It is an arithmetic number, because the mean of its divisors is an integer number (230819625).

Almost surely, 2^21525201280 is an apocalyptic number.

21525201280 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 21525201280, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (29544912000).

21525201280 is an abundant number, since it is smaller than the sum of its proper divisors (37564622720).

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

21525201280 is a wasteful number, since it uses less digits than its factorization.

21525201280 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1905 (or 1893 counting only the distinct ones).

The product of its (nonzero) digits is 3200, while the sum is 28.

Adding to 21525201280 its reverse (8210252512), we get a palindrome (29735453792).

The spelling of 21525201280 in words is "twenty-one billion, five hundred twenty-five million, two hundred one thousand, two hundred eighty".