9999809999 has 2 divisors, whose sum is σ = 9999810000. Its totient is φ = 9999809998.

The previous prime is 9999809987. The next prime is 9999810011. The reversal of 9999809999 is 9999089999.

It is a balanced prime because it is at equal distance from previous prime (9999809987) and next prime (9999810011).

It is a cyclic number.

It is not a de Polignac number, because 9999809999 - 2¹² = 9999805903 is a prime.

It is a super-2 number, since 2×9999809999² (a number of 21 digits) contains 22 as substring.

It is a Sophie Germain prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (9999809929) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 4999904999 + 4999905000.

It is an arithmetic number, because the mean of its divisors is an integer number (4999905000).

Almost surely, 2^9999809999 is an apocalyptic number.

9999809999 is a deficient number, since it is larger than the sum of its proper divisors (1).

9999809999 is an equidigital number, since it uses as much as digits as its factorization.

9999809999 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 344373768, while the sum is 80.

The square root of 9999809999 is about 99999.0499904874. The cubic root of 9999809999 is about 2154.4210451206.

The spelling of 9999809999 in words is "nine billion, nine hundred ninety-nine million, eight hundred nine thousand, nine hundred ninety-nine".