18534243581 has 6 divisors (see below), whose sum is σ = 21560242590. Its totient is φ = 15886494456.

The previous prime is 18534243551. The next prime is 18534243589.

18534243581 is nontrivially palindromic in base 10.

It can be written as a sum of positive squares in only one way, i.e., 11676747481 + 6857496100 = 108059^2 + 82810^2 .

It is not a de Polignac number, because 18534243581 - 2¹⁴ = 18534227197 is a prime.

It is a super-2 number, since 2×18534243581² (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 (18534243589) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 189124886 + ... + 189124983.

It is an arithmetic number, because the mean of its divisors is an integer number (3593373765).

Almost surely, 2^18534243581 is an apocalyptic number.

It is an amenable number.

18534243581 is a deficient number, since it is larger than the sum of its proper divisors (3025999009).

18534243581 is an equidigital number, since it uses as much as digits as its factorization.

18534243581 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 378249883 (or 378249876 counting only the distinct ones).

The product of its digits is 460800, while the sum is 44.

The spelling of 18534243581 in words is "eighteen billion, five hundred thirty-four million, two hundred forty-three thousand, five hundred eighty-one".