21630706560 has 320 divisors, whose sum is σ = 81316501200. Its totient is φ = 5464350720.

The previous prime is 21630706549. The next prime is 21630706561. The reversal of 21630706560 is 6560703612.

21630706560 is a `hidden beast` number, since 21 + 6 + 3 + 0 + 70 + 6 + 560 = 666.

It is a tau number, because it is divible by the number of its divisors (320).

It is a Harshad number since it is a multiple of its sum of digits (36).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21630706561) by changing a digit.

It is a polite number, since it can be written in 39 ways as a sum of consecutive naturals, for example, 973980 + ... + 995940.

Almost surely, 2^21630706560 is an apocalyptic number.

21630706560 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 21630706560, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (40658250600).

21630706560 is an abundant number, since it is smaller than the sum of its proper divisors (59685794640).

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

21630706560 is a wasteful number, since it uses less digits than its factorization.

21630706560 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 22011 (or 21990 counting only the distinct ones).

The product of its (nonzero) digits is 45360, while the sum is 36.

The spelling of 21630706560 in words is "twenty-one billion, six hundred thirty million, seven hundred six thousand, five hundred sixty".