989169991 has 4 divisors (see below), whose sum is σ = 989237752. Its totient is φ = 989102232.

The previous prime is 989169983. The next prime is 989170027. The reversal of 989169991 is 199961989.

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 is a cyclic number.

It is not a de Polignac number, because 989169991 - 2³ = 989169983 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (989169911) 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 in 3 ways as a sum of consecutive naturals, for example, 1956 + ... + 44521.

It is an arithmetic number, because the mean of its divisors is an integer number (247309438).

Almost surely, 2^989169991 is an apocalyptic number.

989169991 is a deficient number, since it is larger than the sum of its proper divisors (67761).

989169991 is a wasteful number, since it uses less digits than its factorization.

989169991 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 67760.

The product of its digits is 2834352, while the sum is 61.

The square root of 989169991 is about 31451.0729705681. The cubic root of 989169991 is about 996.3768858977.

The spelling of 989169991 in words is "nine hundred eighty-nine million, one hundred sixty-nine thousand, nine hundred ninety-one".