9983856521 has 4 divisors (see below), whose sum is σ = 9984700032. Its totient is φ = 9983013012.

The previous prime is 9983856479. The next prime is 9983856637. The reversal of 9983856521 is 1256583899.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 9983856521 - 2¹⁸ = 9983594377 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (9983856121) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 403745 + ... + 427758.

It is an arithmetic number, because the mean of its divisors is an integer number (2496175008).

Almost surely, 2^9983856521 is an apocalyptic number.

It is an amenable number.

9983856521 is a deficient number, since it is larger than the sum of its proper divisors (843511).

9983856521 is a wasteful number, since it uses less digits than its factorization.

9983856521 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 843510.

The product of its digits is 4665600, while the sum is 56.

The square root of 9983856521 is about 99919.2500021893. The cubic root of 9983856521 is about 2153.2747299089.

The spelling of 9983856521 in words is "nine billion, nine hundred eighty-three million, eight hundred fifty-six thousand, five hundred twenty-one".