989892181 has 4 divisors (see below), whose sum is σ = 989988012. Its totient is φ = 989796352.

The previous prime is 989892179. The next prime is 989892187. The reversal of 989892181 is 181298989.

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: 181298989 = 193 ⋅939373.

It can be written as a sum of positive squares in 2 ways, for example, as 555544900 + 434347281 = 23570^2 + 20841^2 .

It is a cyclic number.

It is not a de Polignac number, because 989892181 - 2¹ = 989892179 is a prime.

It is a super-2 number, since 2×989892181² = 1959773060009873522, 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 (989892187) 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, 30250 + ... + 53803.

It is an arithmetic number, because the mean of its divisors is an integer number (247497003).

Almost surely, 2^989892181 is an apocalyptic number.

It is an amenable number.

989892181 is a deficient number, since it is larger than the sum of its proper divisors (95831).

989892181 is a wasteful number, since it uses less digits than its factorization.

989892181 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 95830.

The product of its digits is 746496, while the sum is 55.

The square root of 989892181 is about 31462.5520420706. The cubic root of 989892181 is about 996.6193108200.

The spelling of 989892181 in words is "nine hundred eighty-nine million, eight hundred ninety-two thousand, one hundred eighty-one".