989999999843 has 2 divisors, whose sum is σ = 989999999844. Its totient is φ = 989999999842.

The previous prime is 989999999777. The next prime is 989999999881. The reversal of 989999999843 is 348999999989.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 989999999843 - 2²⁶ = 989932890979 is a prime.

It is not a weakly prime, because it can be changed into another prime (989999999743) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 494999999921 + 494999999922.

It is an arithmetic number, because the mean of its divisors is an integer number (494999999922).

Almost surely, 2^989999999843 is an apocalyptic number.

989999999843 is a deficient number, since it is larger than the sum of its proper divisors (1).

989999999843 is an equidigital number, since it uses as much as digits as its factorization.

989999999843 is an evil number, because the sum of its binary digits is even.

The product of its digits is 33059881728, while the sum is 95.

The spelling of 989999999843 in words is "nine hundred eighty-nine billion, nine hundred ninety-nine million, nine hundred ninety-nine thousand, eight hundred forty-three".