18666872005 has 4 divisors (see below), whose sum is σ = 22400246412. Its totient is φ = 14933497600.

The previous prime is 18666871987. The next prime is 18666872027. The reversal of 18666872005 is 50027866681.

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 3091582404 + 15575289601 = 55602^2 + 124801^2 .

It is not a de Polignac number, because 18666872005 - 2¹⁷ = 18666740933 is a prime.

It is a super-2 number, since 2×18666872005² (a number of 21 digits) contains 22 as substring.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 18666872005.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1866687196 + ... + 1866687205.

It is an arithmetic number, because the mean of its divisors is an integer number (5600061603).

Almost surely, 2^18666872005 is an apocalyptic number.

It is an amenable number.

18666872005 is a deficient number, since it is larger than the sum of its proper divisors (3733374407).

18666872005 is an equidigital number, since it uses as much as digits as its factorization.

18666872005 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3733374406.

The product of its (nonzero) digits is 967680, while the sum is 49.

The spelling of 18666872005 in words is "eighteen billion, six hundred sixty-six million, eight hundred seventy-two thousand, five".