18209509937 has 4 divisors (see below), whose sum is σ = 18211079460. Its totient is φ = 18207940416.

The previous prime is 18209509909. The next prime is 18209509939. The reversal of 18209509937 is 73990590281.

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 8479463056 + 9730046881 = 92084^2 + 98641^2 .

It is a cyclic number.

It is not a de Polignac number, because 18209509937 - 2¹⁶ = 18209444401 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (18209509939) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 767228 + ... + 790605.

It is an arithmetic number, because the mean of its divisors is an integer number (4552769865).

Almost surely, 2^18209509937 is an apocalyptic number.

It is an amenable number.

18209509937 is a deficient number, since it is larger than the sum of its proper divisors (1569523).

18209509937 is a wasteful number, since it uses less digits than its factorization.

18209509937 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1569522.

The product of its (nonzero) digits is 1224720, while the sum is 53.

The spelling of 18209509937 in words is "eighteen billion, two hundred nine million, five hundred nine thousand, nine hundred thirty-seven".