18067781 has 2 divisors, whose sum is σ = 18067782. Its totient is φ = 18067780.

The previous prime is 18067771. The next prime is 18067793. The reversal of 18067781 is 18776081.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 17850625 + 217156 = 4225^2 + 466^2 .

It is a cyclic number.

It is not a de Polignac number, because 18067781 - 2¹⁸ = 17805637 is a prime.

It is a super-2 number, since 2×18067781² = 652889420527922, which contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (18067711) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 9033890 + 9033891.

It is an arithmetic number, because the mean of its divisors is an integer number (9033891).

Almost surely, 2^18067781 is an apocalyptic number.

It is an amenable number.

18067781 is a deficient number, since it is larger than the sum of its proper divisors (1).

18067781 is an equidigital number, since it uses as much as digits as its factorization.

18067781 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 18816, while the sum is 38.

The square root of 18067781 is about 4250.6212487118. The cubic root of 18067781 is about 262.4026838056.

The spelling of 18067781 in words is "eighteen million, sixty-seven thousand, seven hundred eighty-one".