21708470636496 has 720 divisors, whose sum is σ = 73141027674624. Its totient is φ = 5885123641344.

The previous prime is 21708470636483. The next prime is 21708470636581. The reversal of 21708470636496 is 69463607480712.

It is a happy number.

21708470636496 is a `hidden beast` number, since 2 + 1 + 7 + 0 + 84 + 7 + 0 + 63 + 6 + 496 = 666.

It is a Harshad number since it is a multiple of its sum of digits (63).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 143 ways as a sum of consecutive naturals, for example, 28083402766 + ... + 28083403538.

Almost surely, 2^{21708470636496} 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 21708470636496, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (36570513837312).

21708470636496 is an abundant number, since it is smaller than the sum of its proper divisors (51432557038128).

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

21708470636496 is a wasteful number, since it uses less digits than its factorization.

21708470636496 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1348 (or 1302 counting only the distinct ones).

The product of its (nonzero) digits is 73156608, while the sum is 63.

The spelling of 21708470636496 in words is "twenty-one trillion, seven hundred eight billion, four hundred seventy million, six hundred thirty-six thousand, four hundred ninety-six".