18440531761 has 4 divisors (see below), whose sum is σ = 18480883492. Its totient is φ = 18400180032.

The previous prime is 18440531749. The next prime is 18440531783. The reversal of 18440531761 is 16713504481.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 16713504481 = 241 ⋅69350641.

It can be written as a sum of positive squares in 2 ways, for example, as 17146331136 + 1294200625 = 130944^2 + 35975^2 .

It is not a de Polignac number, because 18440531761 - 2⁷ = 18440531633 is a prime.

It is a super-2 number, since 2×18440531761² (a number of 21 digits) contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (18440531701) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 20175180 + ... + 20176093.

It is an arithmetic number, because the mean of its divisors is an integer number (4620220873).

Almost surely, 2^18440531761 is an apocalyptic number.

It is an amenable number.

18440531761 is a deficient number, since it is larger than the sum of its proper divisors (40351731).

18440531761 is an equidigital number, since it uses as much as digits as its factorization.

18440531761 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 40351730.

The product of its (nonzero) digits is 80640, while the sum is 40.

The spelling of 18440531761 in words is "eighteen billion, four hundred forty million, five hundred thirty-one thousand, seven hundred sixty-one".