9999858809 has 2 divisors, whose sum is σ = 9999858810. Its totient is φ = 9999858808.

The previous prime is 9999858797. The next prime is 9999858863. The reversal of 9999858809 is 9088589999.

It is a happy number.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 9760847209 + 239011600 = 98797^2 + 15460^2 .

It is a cyclic number.

It is not a de Polignac number, because 9999858809 - 2⁸ = 9999858553 is a prime.

It is not a weakly prime, because it can be changed into another prime (9999858889) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 4999929404 + 4999929405.

It is an arithmetic number, because the mean of its divisors is an integer number (4999929405).

Almost surely, 2^9999858809 is an apocalyptic number.

It is an amenable number.

9999858809 is a deficient number, since it is larger than the sum of its proper divisors (1).

9999858809 is an equidigital number, since it uses as much as digits as its factorization.

9999858809 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 151165440, while the sum is 74.

The square root of 9999858809 is about 99999.2940425081. The cubic root of 9999858809 is about 2154.4245504246.

The spelling of 9999858809 in words is "nine billion, nine hundred ninety-nine million, eight hundred fifty-eight thousand, eight hundred nine".