21706610688 has 672 divisors, whose sum is σ = 77915335680. Its totient is φ = 5912248320.

The previous prime is 21706610687. The next prime is 21706610741. The reversal of 21706610688 is 88601660712.

It is a happy number.

21706610688 is a `hidden beast` number, since 21 + 7 + 0 + 6 + 610 + 6 + 8 + 8 = 666.

It is a tau number, because it is divible by the number of its divisors (672).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21706610687) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 55 ways as a sum of consecutive naturals, for example, 323979231 + ... + 323979297.

It is an arithmetic number, because the mean of its divisors is an integer number (115945440).

Almost surely, 2^21706610688 is an apocalyptic number.

21706610688 is a gapful number since it is divisible by the number (28) 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 21706610688, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (38957667840).

21706610688 is an abundant number, since it is smaller than the sum of its proper divisors (56208724992).

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

21706610688 is an frugal number, since it uses more digits than its factorization.

21706610688 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 145 (or 110 counting only the distinct ones).

The product of its (nonzero) digits is 193536, while the sum is 45.

The spelling of 21706610688 in words is "twenty-one billion, seven hundred six million, six hundred ten thousand, six hundred eighty-eight".