21709467648 has 468 divisors, whose sum is σ = 71604280384. Its totient is φ = 6325862400.

The previous prime is 21709467643. The next prime is 21709467671. The reversal of 21709467648 is 84676490712.

21709467648 is a `hidden beast` number, since 2 + 170 + 9 + 467 + 6 + 4 + 8 = 666.

It is a junction number, because it is equal to n+sod(n) for n = 21709467594 and 21709467603.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21709467643) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 35 ways as a sum of consecutive naturals, for example, 138276786 + ... + 138276942.

Almost surely, 2^21709467648 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 21709467648, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (35802140192).

21709467648 is an abundant number, since it is smaller than the sum of its proper divisors (49894812736).

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

21709467648 is a wasteful number, since it uses less digits than its factorization.

21709467648 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 240 (or 204 counting only the distinct ones).

The product of its (nonzero) digits is 4064256, while the sum is 54.

The spelling of 21709467648 in words is "twenty-one billion, seven hundred nine million, four hundred sixty-seven thousand, six hundred forty-eight".