18550729 has 2 divisors, whose sum is σ = 18550730. Its totient is φ = 18550728.

The previous prime is 18550717. The next prime is 18550733. The reversal of 18550729 is 92705581.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 14077504 + 4473225 = 3752^2 + 2115^2 .

It is an emirp because it is prime and its reverse (92705581) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 18550729 - 2¹¹ = 18548681 is a prime.

It is not a weakly prime, because it can be changed into another prime (18550739) 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 as a sum of consecutive naturals, namely, 9275364 + 9275365.

It is an arithmetic number, because the mean of its divisors is an integer number (9275365).

Almost surely, 2^18550729 is an apocalyptic number.

It is an amenable number.

18550729 is a deficient number, since it is larger than the sum of its proper divisors (1).

18550729 is an equidigital number, since it uses as much as digits as its factorization.

18550729 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 25200, while the sum is 37.

The square root of 18550729 is about 4307.0557228808. The cubic root of 18550729 is about 264.7201460017.

The spelling of 18550729 in words is "eighteen million, five hundred fifty thousand, seven hundred twenty-nine".