18385780409 has 2 divisors, whose sum is σ = 18385780410. Its totient is φ = 18385780408.

The previous prime is 18385780397. The next prime is 18385780417. The reversal of 18385780409 is 90408758381.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 15071245225 + 3314535184 = 122765^2 + 57572^2 .

It is a cyclic number.

It is not a de Polignac number, because 18385780409 - 2¹² = 18385776313 is a prime.

It is not a weakly prime, because it can be changed into another prime (18385780459) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 9192890204 + 9192890205.

It is an arithmetic number, because the mean of its divisors is an integer number (9192890205).

Almost surely, 2^18385780409 is an apocalyptic number.

It is an amenable number.

18385780409 is a deficient number, since it is larger than the sum of its proper divisors (1).

18385780409 is an equidigital number, since it uses as much as digits as its factorization.

18385780409 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 1935360, while the sum is 53.

The spelling of 18385780409 in words is "eighteen billion, three hundred eighty-five million, seven hundred eighty thousand, four hundred nine".