989919989 has 2 divisors, whose sum is σ = 989919990.
Its totient is φ = 989919988.
The previous prime is 989919961. The next prime is 989920021.
989919989 is nontrivially palindromic in base 10.
It is a weak prime.
It can be written as a sum of positive squares in only one way, i.e., 719580625 + 270339364 = 26825^2 + 16442^2
It is a palprime.
It is a cyclic number.
It is not a de Polignac number, because 989919989 - 212 = 989915893 is a prime.
It is a Chen prime.
It is a congruent number.
It is not a weakly prime, because it can be changed into another prime (989919389) 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, 494959994 + 494959995.
It is an arithmetic number, because the mean of its divisors is an integer number (494959995).
Almost surely, 2989919989 is an apocalyptic number.
It is an amenable number.
989919989 is a deficient number, since it is larger than the sum of its proper divisors (1).
989919989 is an equidigital number, since it uses as much as digits as its factorization.
989919989 is an odious number, because the sum of its binary digits is odd.
The product of its digits is 34012224, while the sum is 71.
The square root of 989919989 is about 31462.9939611601.
The cubic root of 989919989 is about 996.6286430587.
The spelling of 989919989 in words is "nine hundred eighty-nine million, nine hundred nineteen thousand, nine hundred eighty-nine".