18385729 has 2 divisors, whose sum is σ = 18385730. Its totient is φ = 18385728.

The previous prime is 18385727. The next prime is 18385733. The reversal of 18385729 is 92758381.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 15000129 + 3385600 = 3873^2 + 1840^2 .

It is a cyclic number.

It is not a de Polignac number, because 18385729 - 2¹ = 18385727 is a prime.

It is a super-2 number, since 2×18385729² = 676070061722882, which contains 22 as substring.

Together with 18385727, it forms a pair of twin primes.

It is not a weakly prime, because it can be changed into another prime (18385727) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 9192864 + 9192865.

It is an arithmetic number, because the mean of its divisors is an integer number (9192865).

Almost surely, 2^18385729 is an apocalyptic number.

It is an amenable number.

18385729 is a deficient number, since it is larger than the sum of its proper divisors (1).

18385729 is an equidigital number, since it uses as much as digits as its factorization.

18385729 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 120960, while the sum is 43.

The square root of 18385729 is about 4287.8583232192. The cubic root of 18385729 is about 263.9329537807.

The spelling of 18385729 in words is "eighteen million, three hundred eighty-five thousand, seven hundred twenty-nine".