18138208444 has 12 divisors (see below), whose sum is σ = 32340768264. Its totient is φ = 8897988944.

The previous prime is 18138208441. The next prime is 18138208471. The reversal of 18138208444 is 44480283181.

It is a super-2 number, since 2×18138208444² (a number of 21 digits) contains 22 as substring.

It is a self number, because there is not a number n which added to its sum of digits gives 18138208444.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (18138208441) 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, 42778582 + ... + 42779005.

It is an arithmetic number, because the mean of its divisors is an integer number (2695064022).

Almost surely, 2^18138208444 is an apocalyptic number.

It is an amenable number.

18138208444 is a deficient number, since it is larger than the sum of its proper divisors (14202559820).

18138208444 is a wasteful number, since it uses less digits than its factorization.

18138208444 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 85557644 (or 85557642 counting only the distinct ones).

The product of its (nonzero) digits is 196608, while the sum is 43.

The spelling of 18138208444 in words is "eighteen billion, one hundred thirty-eight million, two hundred eight thousand, four hundred forty-four".