989878789 has 4 divisors (see below), whose sum is σ = 989960940.
Its totient is φ = 989796640.
The previous prime is 989878783. The next prime is 989878793. The reversal of 989878789 is 987878989.
989878789 is an esthetic number in base 10, because in such base its adjacent digits differ by 1.
It is a semiprime because it is the product of two primes, and also a brilliant number, because the two primes have the same length.
It can be written as a sum of positive squares in 2 ways, for example, as 842450625 + 147428164 = 29025^2 + 12142^2
It is a cyclic number.
It is not a de Polignac number, because 989878789 - 27 = 989878661 is a prime.
It is an alternating number because its digits alternate between odd and even.
It is a Duffinian number.
It is a congruent number.
It is not an unprimeable number, because it can be changed into a prime (989878783) by changing a digit.
It is a pernicious number, because its binary representation contains a prime number (11) of ones.
It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 19072 + ... + 48409.
It is an arithmetic number, because the mean of its divisors is an integer number (247490235).
Almost surely, 2989878789 is an apocalyptic number.
It is an amenable number.
989878789 is a deficient number, since it is larger than the sum of its proper divisors (82151).
989878789 is a wasteful number, since it uses less digits than its factorization.
989878789 is an odious number, because the sum of its binary digits is odd.
The sum of its prime factors is 82150.
The product of its digits is 146313216, while the sum is 73.
The square root of 989878789 is about 31462.3392169114.
The cubic root of 989878789 is about 996.6148164632.
The spelling of 989878789 in words is "nine hundred eighty-nine million, eight hundred seventy-eight thousand, seven hundred eighty-nine".