9908684721 has 40 divisors (see below), whose sum is σ = 16454729984. Its totient is φ = 5900934240.

The previous prime is 9908684683. The next prime is 9908684729. The reversal of 9908684721 is 1274868099.

9908684721 is a `hidden beast` number, since 9 + 90 + 86 + 8 + 472 + 1 = 666.

9908684721 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is not a de Polignac number, because 9908684721 - 2¹⁵ = 9908651953 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (9908684729) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 39 ways as a sum of consecutive naturals, for example, 119131 + ... + 184416.

Almost surely, 2^9908684721 is an apocalyptic number.

It is an amenable number.

9908684721 is a deficient number, since it is larger than the sum of its proper divisors (6546045263).

9908684721 is a wasteful number, since it uses less digits than its factorization.

9908684721 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 303603 (or 303594 counting only the distinct ones).

The product of its (nonzero) digits is 1741824, while the sum is 54.

The square root of 9908684721 is about 99542.3765087011. The cubic root of 9908684721 is about 2147.8568671986.

The spelling of 9908684721 in words is "nine billion, nine hundred eight million, six hundred eighty-four thousand, seven hundred twenty-one".