18328729 has 2 divisors, whose sum is σ = 18328730. Its totient is φ = 18328728.

The previous prime is 18328693. The next prime is 18328759. The reversal of 18328729 is 92782381.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 15681600 + 2647129 = 3960^2 + 1627^2 .

It is an emirp because it is prime and its reverse (92782381) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 18328729 - 2¹¹ = 18326681 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 18328691 and 18328700.

It is not a weakly prime, because it can be changed into another prime (18328759) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is an upside-down number.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 9164364 + 9164365.

It is an arithmetic number, because the mean of its divisors is an integer number (9164365).

Almost surely, 2^18328729 is an apocalyptic number.

It is an amenable number.

18328729 is a deficient number, since it is larger than the sum of its proper divisors (1).

18328729 is an equidigital number, since it uses as much as digits as its factorization.

18328729 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 48384, while the sum is 40.

The square root of 18328729 is about 4281.2064888300. The cubic root of 18328729 is about 263.6599204224.

The spelling of 18328729 in words is "eighteen million, three hundred twenty-eight thousand, seven hundred twenty-nine".