989898181 has 4 divisors (see below), whose sum is σ = 989968012. Its totient is φ = 989828352.

The previous prime is 989898163. The next prime is 989898197. The reversal of 989898181 is 181898989.

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, and also an emirpimes, since its reverse is a distinct semiprime: 181898989 = 19 ⋅9573631.

It can be written as a sum of positive squares in 2 ways, for example, as 770562081 + 219336100 = 27759^2 + 14810^2 .

It is a cyclic number.

It is not a de Polignac number, because 989898181 - 2⁵ = 989898149 is a prime.

It is a super-2 number, since 2×989898181² = 1959796817494217522, which contains 22 as substring.

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 (989898131) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 5250 + ... + 44803.

It is an arithmetic number, because the mean of its divisors is an integer number (247492003).

Almost surely, 2^989898181 is an apocalyptic number.

It is an amenable number.

989898181 is a deficient number, since it is larger than the sum of its proper divisors (69831).

989898181 is a wasteful number, since it uses less digits than its factorization.

989898181 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 69830.

The product of its digits is 2985984, while the sum is 61.

The square root of 989898181 is about 31462.6473933774. The cubic root of 989898181 is about 996.6213244076.

The spelling of 989898181 in words is "nine hundred eighty-nine million, eight hundred ninety-eight thousand, one hundred eighty-one".