9998575821 has 32 divisors (see below), whose sum is σ = 15958320000. Its totient is φ = 6150587904.

The previous prime is 9998575799. The next prime is 9998575871. The reversal of 9998575821 is 1285758999.

9998575821 is digitally balanced in base 3, because in such base it contains all the possibile digits an equal number of times.

It is not a de Polignac number, because 9998575821 - 2⁶ = 9998575757 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (9998575871) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 1445830 + ... + 1452728.

It is an arithmetic number, because the mean of its divisors is an integer number (498697500).

Almost surely, 2^9998575821 is an apocalyptic number.

It is an amenable number.

9998575821 is a deficient number, since it is larger than the sum of its proper divisors (5959744179).

9998575821 is a wasteful number, since it uses less digits than its factorization.

9998575821 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 11050 (or 11044 counting only the distinct ones).

The product of its digits is 16329600, while the sum is 63.

The square root of 9998575821 is about 99992.8788514462. The cubic root of 9998575821 is about 2154.3324084881.

The spelling of 9998575821 in words is "nine billion, nine hundred ninety-eight million, five hundred seventy-five thousand, eight hundred twenty-one".