18758685781 has 12 divisors (see below), whose sum is σ = 20644033900. Its totient is φ = 17032688640.

The previous prime is 18758685719. The next prime is 18758685787.

18758685781 is nontrivially palindromic in base 10.

It can be written as a sum of positive squares in 2 ways, for example, as 12861828100 + 5896857681 = 113410^2 + 76791^2 .

It is not a de Polignac number, because 18758685781 - 2¹¹ = 18758683733 is a prime.

It is a super-2 number, since 2×18758685781² (a number of 21 digits) contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (18758685787) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 6805 + ... + 193813.

Almost surely, 2^18758685781 is an apocalyptic number.

18758685781 is a gapful number since it is divisible by the number (11) formed by its first and last digit.

It is an amenable number.

18758685781 is a deficient number, since it is larger than the sum of its proper divisors (1885348119).

18758685781 is a wasteful number, since it uses less digits than its factorization.

18758685781 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 187860 (or 187849 counting only the distinct ones).

The product of its digits is 30105600, while the sum is 64.

The spelling of 18758685781 in words is "eighteen billion, seven hundred fifty-eight million, six hundred eighty-five thousand, seven hundred eighty-one".