18505440438 has 8 divisors (see below), whose sum is σ = 37010880888. Its totient is φ = 6168480144.

The previous prime is 18505440427. The next prime is 18505440461. The reversal of 18505440438 is 83404450581.

It is a happy number.

It is a sphenic number, since it is the product of 3 distinct primes.

18505440438 is an admirable number.

It is a self number, because there is not a number n which added to its sum of digits gives 18505440438.

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, 1542120031 + ... + 1542120042.

It is an arithmetic number, because the mean of its divisors is an integer number (4626360111).

Almost surely, 2^18505440438 is an apocalyptic number.

18505440438 is a primitive abundant number, since it is smaller than the sum of its proper divisors, none of which is abundant.

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

18505440438 is a wasteful number, since it uses less digits than its factorization.

18505440438 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3084240078.

The product of its (nonzero) digits is 307200, while the sum is 42.

The spelling of 18505440438 in words is "eighteen billion, five hundred five million, four hundred forty thousand, four hundred thirty-eight".