21010066560 has 384 divisors, whose sum is σ = 83467987200. Its totient is φ = 4770275328.

The previous prime is 21010066559. The next prime is 21010066579. The reversal of 21010066560 is 6566001012.

It is a happy number.

21010066560 is a `hidden beast` number, since 2 + 1 + 0 + 1 + 0 + 0 + 6 + 656 + 0 = 666.

It is a tau number, because it is divible by the number of its divisors (384).

It is a super-3 number, since 3×21010066560³ (a number of 32 digits) contains 333 as substring.

It is an unprimeable number.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 6328581 + ... + 6331899.

It is an arithmetic number, because the mean of its divisors is an integer number (217364550).

Almost surely, 2^21010066560 is an apocalyptic number.

21010066560 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 21010066560, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (41733993600).

21010066560 is an abundant number, since it is smaller than the sum of its proper divisors (62457920640).

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

21010066560 is a wasteful number, since it uses less digits than its factorization.

21010066560 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3508 (or 3493 counting only the distinct ones).

The product of its (nonzero) digits is 2160, while the sum is 27.

Adding to 21010066560 its reverse (6566001012), we get a palindrome (27576067572).

The spelling of 21010066560 in words is "twenty-one billion, ten million, sixty-six thousand, five hundred sixty".