18009473809 has 4 divisors (see below), whose sum is σ = 18011194480. Its totient is φ = 18007753140.

The previous prime is 18009473791. The next prime is 18009473843. The reversal of 18009473809 is 90837490081.

It is a happy number.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 18009473809 - 2¹¹ = 18009471761 is a prime.

It is a super-2 number, since 2×18009473809² (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 (18009473899) 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, 844539 + ... + 865600.

It is an arithmetic number, because the mean of its divisors is an integer number (4502798620).

Almost surely, 2^18009473809 is an apocalyptic number.

It is an amenable number.

18009473809 is a deficient number, since it is larger than the sum of its proper divisors (1720671).

18009473809 is a wasteful number, since it uses less digits than its factorization.

18009473809 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1720670.

The product of its (nonzero) digits is 435456, while the sum is 49.

The spelling of 18009473809 in words is "eighteen billion, nine million, four hundred seventy-three thousand, eight hundred nine".