9721950561648 has 400 divisors, whose sum is σ = 30574339783680. Its totient is φ = 2964598382592.

The previous prime is 9721950561637. The next prime is 9721950561679. The reversal of 9721950561648 is 8461650591279.

9721950561648 is a `hidden beast` number, since 9 + 7 + 2 + 1 + 9 + 5 + 0 + 5 + 616 + 4 + 8 = 666.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 79 ways as a sum of consecutive naturals, for example, 2629684536 + ... + 2629688232.

Almost surely, 2^{9721950561648} 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 9721950561648, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (15287169891840).

9721950561648 is an abundant number, since it is smaller than the sum of its proper divisors (20852389222032).

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

9721950561648 is a wasteful number, since it uses less digits than its factorization.

9721950561648 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5086 (or 5071 counting only the distinct ones).

The product of its (nonzero) digits is 32659200, while the sum is 63.

The spelling of 9721950561648 in words is "nine trillion, seven hundred twenty-one billion, nine hundred fifty million, five hundred sixty-one thousand, six hundred forty-eight".