21618984960 has 288 divisors, whose sum is σ = 77520807000. Its totient is φ = 5565579264.

The previous prime is 21618984917. The next prime is 21618984971. The reversal of 21618984960 is 6948981612.

21618984960 is a `hidden beast` number, since 2 + 1 + 61 + 8 + 98 + 496 + 0 = 666.

It can be written as a sum of positive squares in 4 ways, for example, as 10729645056 + 10889339904 = 103584^2 + 104352^2 .

It is a tau number, because it is divible by the number of its divisors (288).

It is a junction number, because it is equal to n+sod(n) for n = 21618984897 and 21618984906.

It is an unprimeable number.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 2668596 + ... + 2676684.

Almost surely, 2^21618984960 is an apocalyptic number.

21618984960 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 21618984960, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (38760403500).

21618984960 is an abundant number, since it is smaller than the sum of its proper divisors (55901822040).

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

21618984960 is a wasteful number, since it uses less digits than its factorization.

21618984960 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 8151 (or 8128 counting only the distinct ones).

The product of its (nonzero) digits is 1492992, while the sum is 54.

The spelling of 21618984960 in words is "twenty-one billion, six hundred eighteen million, nine hundred eighty-four thousand, nine hundred sixty".