18056781 has 12 divisors (see below), whose sum is σ = 26120640. Its totient is φ = 12020040.

The previous prime is 18056761. The next prime is 18056803. The reversal of 18056781 is 18765081.

18056781 is a `hidden beast` number, since 18 + 0 + 567 + 81 = 666.

It is not a de Polignac number, because 18056781 - 2⁷ = 18056653 is a prime.

It is a super-2 number, since 2×18056781² = 652094680163922, which contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (18056761) 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 in 11 ways as a sum of consecutive naturals, for example, 8386 + ... + 10316.

It is an arithmetic number, because the mean of its divisors is an integer number (2176720).

Almost surely, 2^18056781 is an apocalyptic number.

It is an amenable number.

18056781 is a deficient number, since it is larger than the sum of its proper divisors (8063859).

18056781 is a wasteful number, since it uses less digits than its factorization.

18056781 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2976 (or 2973 counting only the distinct ones).

The product of its (nonzero) digits is 13440, while the sum is 36.

The square root of 18056781 is about 4249.3271232043. The cubic root of 18056781 is about 262.3494211224.

The spelling of 18056781 in words is "eighteen million, fifty-six thousand, seven hundred eighty-one".