181409689 has 4 divisors (see below), whose sum is σ = 181436724. Its totient is φ = 181382656.

The previous prime is 181409659. The next prime is 181409693. The reversal of 181409689 is 986904181.

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 115670025 + 65739664 = 10755^2 + 8108^2 .

It is a cyclic number.

It is not a de Polignac number, because 181409689 - 2¹¹ = 181407641 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (181409609) 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, 5049 + ... + 19705.

It is an arithmetic number, because the mean of its divisors is an integer number (45359181).

Almost surely, 2^181409689 is an apocalyptic number.

It is an amenable number.

181409689 is a deficient number, since it is larger than the sum of its proper divisors (27035).

181409689 is a wasteful number, since it uses less digits than its factorization.

181409689 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 27034.

The product of its (nonzero) digits is 124416, while the sum is 46.

The square root of 181409689 is about 13468.8414126828. The cubic root of 181409689 is about 566.0917507451.

The spelling of 181409689 in words is "one hundred eighty-one million, four hundred nine thousand, six hundred eighty-nine".