21288550560 has 288 divisors, whose sum is σ = 72040207680. Its totient is φ = 5265850368.

The previous prime is 21288550537. The next prime is 21288550561. The reversal of 21288550560 is 6505588212.

It is a hoax number, since the sum of its digits (42) coincides with the sum of the digits of its distinct prime factors.

It is not an unprimeable number, because it can be changed into a prime (21288550561) by changing a digit.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 153154971 + ... + 153155109.

It is an arithmetic number, because the mean of its divisors is an integer number (250139610).

Almost surely, 2^21288550560 is an apocalyptic number.

21288550560 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 21288550560, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (36020103840).

21288550560 is an abundant number, since it is smaller than the sum of its proper divisors (50751657120).

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

21288550560 is a wasteful number, since it uses less digits than its factorization.

21288550560 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 448 (or 303 counting only the distinct ones).

The product of its (nonzero) digits is 192000, while the sum is 42.

The spelling of 21288550560 in words is "twenty-one billion, two hundred eighty-eight million, five hundred fifty thousand, five hundred sixty".