18129409 has 2 divisors, whose sum is σ = 18129410. Its totient is φ = 18129408.

The previous prime is 18129337. The next prime is 18129413. The reversal of 18129409 is 90492181.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 17850625 + 278784 = 4225^2 + 528^2 .

It is a cyclic number.

It is not a de Polignac number, because 18129409 - 2⁷ = 18129281 is a prime.

It is not a weakly prime, because it can be changed into another prime (18159409) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (7) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 9064704 + 9064705.

It is an arithmetic number, because the mean of its divisors is an integer number (9064705).

Almost surely, 2^18129409 is an apocalyptic number.

It is an amenable number.

18129409 is a deficient number, since it is larger than the sum of its proper divisors (1).

18129409 is an equidigital number, since it uses as much as digits as its factorization.

18129409 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 5184, while the sum is 34.

The square root of 18129409 is about 4257.8643707850. The cubic root of 18129409 is about 262.7006912715.

The spelling of 18129409 in words is "eighteen million, one hundred twenty-nine thousand, four hundred nine".