18781577518781 has 16 divisors (see below), whose sum is σ = 23421667000320. Its totient is φ = 14631449063280.

The previous prime is 18781577518771. The next prime is 18781577518783.

18781577518781 is nontrivially palindromic in base 10.

It is a de Polignac number, because none of the positive numbers 2^k-18781577518781 is a prime.

It is a super-2 number, since 2×18781577518781² (a number of 27 digits) contains 22 as substring.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 18781577518699 and 18781577518708.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (18781577518783) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 29233541 + ... + 29869098.

It is an arithmetic number, because the mean of its divisors is an integer number (1463854187520).

Almost surely, 2^{18781577518781} is an apocalyptic number.

18781577518781 is a gapful number since it is divisible by the number (11) formed by its first and last digit.

It is an amenable number.

18781577518781 is a deficient number, since it is larger than the sum of its proper divisors (4640089481539).

18781577518781 is a wasteful number, since it uses less digits than its factorization.

18781577518781 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 59106784.

The product of its digits is 245862400, while the sum is 74.

The spelling of 18781577518781 in words is "eighteen trillion, seven hundred eighty-one billion, five hundred seventy-seven million, five hundred eighteen thousand, seven hundred eighty-one".