9808723521 has 9 divisors (see below), whose sum is σ = 14168585379. Its totient is φ = 6538950936.

The previous prime is 9808723513. The next prime is 9808723537. The reversal of 9808723521 is 1253278089.

It is a happy number.

The square root of 9808723521 is 99039.

It is a perfect power (a square), and thus also a powerful number.

9808723521 is digitally balanced in base 3, because in such base it contains all the possibile digits an equal number of times.

It can be written as a sum of positive squares in only one way, i.e., 1715202225 + 8093521296 = 41415^2 + 89964^2 .

It is a tau number, because it is divible by the number of its divisors (9).

It is not a de Polignac number, because 9808723521 - 2³ = 9808723513 is a prime.

It is a super-2 number, since 2×9808723521² (a number of 21 digits) contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (9808723021) by changing a digit.

It is a polite number, since it can be written in 8 ways as a sum of consecutive naturals, for example, 280611 + ... + 313623.

Almost surely, 2^9808723521 is an apocalyptic number.

9808723521 is the 99039-th square number.

9808723521 is the 49520-th centered octagonal number.

It is an amenable number.

9808723521 is a deficient number, since it is larger than the sum of its proper divisors (4359861858).

9808723521 is an frugal number, since it uses more digits than its factorization.

9808723521 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 66032 (or 33016 counting only the distinct ones).

The product of its (nonzero) digits is 241920, while the sum is 45.

The cubic root of 9808723521 is about 2140.6097427654.

The spelling of 9808723521 in words is "nine billion, eight hundred eight million, seven hundred twenty-three thousand, five hundred twenty-one".