181989169 has 8 divisors (see below), whose sum is σ = 186885608. Its totient is φ = 177154560.

The previous prime is 181989151. The next prime is 181989209. The reversal of 181989169 is 961989181.

It can be written as a sum of positive squares in 4 ways, for example, as 90000 + 181899169 = 300^2 + 13487^2 .

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 181989169 - 2⁹ = 181988657 is a prime.

It is a super-2 number, since 2×181989169² = 66240115266621122, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (181989139) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 9462 + ... + 21295.

It is an arithmetic number, because the mean of its divisors is an integer number (23360701).

Almost surely, 2^181989169 is an apocalyptic number.

It is an amenable number.

181989169 is a deficient number, since it is larger than the sum of its proper divisors (4896439).

181989169 is an equidigital number, since it uses as much as digits as its factorization.

181989169 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 30915.

The product of its digits is 279936, while the sum is 52.

The square root of 181989169 is about 13490.3361336921. The cubic root of 181989169 is about 566.6938688595.

The spelling of 181989169 in words is "one hundred eighty-one million, nine hundred eighty-nine thousand, one hundred sixty-nine".