9997021809 has 32 divisors (see below), whose sum is σ = 15155112960. Its totient is φ = 6510651264.

The previous prime is 9997021807. The next prime is 9997021831. The reversal of 9997021809 is 9081207999.

9997021809 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 9997021809 - 2¹ = 9997021807 is a prime.

It is not an unprimeable number, because it can be changed into a prime (9997021807) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 318432 + ... + 348414.

It is an arithmetic number, because the mean of its divisors is an integer number (473597280).

Almost surely, 2^9997021809 is an apocalyptic number.

It is an amenable number.

9997021809 is a deficient number, since it is larger than the sum of its proper divisors (5158091151).

9997021809 is a wasteful number, since it uses less digits than its factorization.

9997021809 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 30278 (or 30272 counting only the distinct ones).

The product of its (nonzero) digits is 734832, while the sum is 54.

The square root of 9997021809 is about 99985.1079361322. The cubic root of 9997021809 is about 2154.2207915293.

The spelling of 9997021809 in words is "nine billion, nine hundred ninety-seven million, twenty-one thousand, eight hundred nine".