181409609 has 2 divisors, whose sum is σ = 181409610. Its totient is φ = 181409608.

The previous prime is 181409563. The next prime is 181409611. The reversal of 181409609 is 906904181.

It is a happy number.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 165688384 + 15721225 = 12872^2 + 3965^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-181409609 is a prime.

Together with 181409611, it forms a pair of twin primes.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (181409629) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 90704804 + 90704805.

It is an arithmetic number, because the mean of its divisors is an integer number (90704805).

Almost surely, 2^181409609 is an apocalyptic number.

It is an amenable number.

181409609 is a deficient number, since it is larger than the sum of its proper divisors (1).

181409609 is an equidigital number, since it uses as much as digits as its factorization.

181409609 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 15552, while the sum is 38.

The square root of 181409609 is about 13468.8384428651. The cubic root of 181409609 is about 566.0916675314.

The spelling of 181409609 in words is "one hundred eighty-one million, four hundred nine thousand, six hundred nine".