21558722560 has 100 divisors (see below), whose sum is σ = 51942259188. Its totient is φ = 8589934592.

The previous prime is 21558722557. The next prime is 21558722561. The reversal of 21558722560 is 6522785512.

It can be written as a sum of positive squares in 2 ways, for example, as 16122904576 + 5435817984 = 126976^2 + 73728^2 .

It is a super-3 number, since 3×21558722560³ (a number of 32 digits) contains 333 as substring.

It is a zygodrome in base 4.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21558722561) by changing a digit.

In principle, a polygon with 21558722560 sides can be constructed with ruler and compass.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 83885952 + ... + 83886208.

Almost surely, 2^21558722560 is an apocalyptic number.

21558722560 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 21558722560, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (25971129594).

21558722560 is an abundant number, since it is smaller than the sum of its proper divisors (30383536628).

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

21558722560 is an frugal number, since it uses more digits than its factorization.

21558722560 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 310 (or 264 counting only the distinct ones).

The product of its (nonzero) digits is 336000, while the sum is 43.

The spelling of 21558722560 in words is "twenty-one billion, five hundred fifty-eight million, seven hundred twenty-two thousand, five hundred sixty".