99999989 has 2 divisors, whose sum is σ = 99999990.
Its totient is φ = 99999988.
The previous prime is 99999971. The next prime is 100000007. The reversal of 99999989 is 98999999.
It is a balanced prime because it is at equal distance from previous prime (99999971) and next prime (100000007).
It can be written as a sum of positive squares in only one way, i.e., 71537764 + 28462225 = 8458^2 + 5335^2
It is a cyclic number.
It is not a de Polignac number, because 99999989 - 212 = 99995893 is a prime.
It is a congruent number.
It is not a weakly prime, because it can be changed into another prime (99999959) by changing a digit.
It is a pernicious number, because its binary representation contains a prime number (17) of ones.
It is a polite number, since it can be written as a sum of consecutive naturals, namely, 49999994 + 49999995.
It is an arithmetic number, because the mean of its divisors is an integer number (49999995).
Almost surely, 299999989 is an apocalyptic number.
It is an amenable number.
99999989 is a deficient number, since it is larger than the sum of its proper divisors (1).
99999989 is an equidigital number, since it uses as much as digits as its factorization.
99999989 is an odious number, because the sum of its binary digits is odd.
The product of its digits is 38263752, while the sum is 71.
The square root of 99999989 is about 9999.9994500000.
Note that the first 3 decimals coincide.
The cubic root of 99999989 is about 464.1588663421.
The spelling of 99999989 in words is "ninety-nine million, nine hundred ninety-nine thousand, nine hundred eighty-nine".