9988888909 has 2 divisors, whose sum is σ = 9988888910. Its totient is φ = 9988888908.

The previous prime is 9988888837. The next prime is 9988888961. The reversal of 9988888909 is 9098888899.

It is a happy number.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 6469789225 + 3519099684 = 80435^2 + 59322^2 .

It is an emirp because it is prime and its reverse (9098888899) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 9988888909 - 2¹¹ = 9988886861 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (9988888969) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 4994444454 + 4994444455.

It is an arithmetic number, because the mean of its divisors is an integer number (4994444455).

Almost surely, 2^9988888909 is an apocalyptic number.

It is an amenable number.

9988888909 is a deficient number, since it is larger than the sum of its proper divisors (1).

9988888909 is an equidigital number, since it uses as much as digits as its factorization.

9988888909 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 214990848, while the sum is 76.

The square root of 9988888909 is about 99944.4291043778. The cubic root of 9988888909 is about 2153.6364569877.

It can be divided in two parts, 998888890 and 9, that added together give a palindrome (998888899).

The spelling of 9988888909 in words is "nine billion, nine hundred eighty-eight million, eight hundred eighty-eight thousand, nine hundred nine".