18042804581 has 4 divisors (see below), whose sum is σ = 18202475532. Its totient is φ = 17883133632.

The previous prime is 18042804557. The next prime is 18042804583. The reversal of 18042804581 is 18540824081.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 197852356 + 17844952225 = 14066^2 + 133585^2 .

It is a cyclic number.

It is not a de Polignac number, because 18042804581 - 2²² = 18038610277 is a prime.

It is a super-2 number, since 2×18042804581² (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 (18042804583) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 79835306 + ... + 79835531.

It is an arithmetic number, because the mean of its divisors is an integer number (4550618883).

Almost surely, 2^18042804581 is an apocalyptic number.

It is an amenable number.

18042804581 is a deficient number, since it is larger than the sum of its proper divisors (159670951).

18042804581 is a wasteful number, since it uses less digits than its factorization.

18042804581 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 159670950.

The product of its (nonzero) digits is 81920, while the sum is 41.

The spelling of 18042804581 in words is "eighteen billion, forty-two million, eight hundred four thousand, five hundred eighty-one".