18772806109 has 4 divisors (see below), whose sum is σ = 18802093500. Its totient is φ = 18743518720.

The previous prime is 18772806097. The next prime is 18772806131. The reversal of 18772806109 is 90160827781.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 90160827781 = 277 ⋅325490353.

It can be written as a sum of positive squares in 2 ways, for example, as 15552584100 + 3220222009 = 124710^2 + 56747^2 .

It is a cyclic number.

It is not a de Polignac number, because 18772806109 - 2⁵ = 18772806077 is a prime.

It is a super-2 number, since 2×18772806109² (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 (18772806139) 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, 14642734 + ... + 14644015.

It is an arithmetic number, because the mean of its divisors is an integer number (4700523375).

Almost surely, 2^18772806109 is an apocalyptic number.

It is an amenable number.

18772806109 is a deficient number, since it is larger than the sum of its proper divisors (29287391).

18772806109 is an equidigital number, since it uses as much as digits as its factorization.

18772806109 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 29287390.

The product of its (nonzero) digits is 338688, while the sum is 49.

The spelling of 18772806109 in words is "eighteen billion, seven hundred seventy-two million, eight hundred six thousand, one hundred nine".