18818187644 has 12 divisors (see below), whose sum is σ = 32935761768. Its totient is φ = 9407970000.

The previous prime is 18818187631. The next prime is 18818187649. The reversal of 18818187644 is 44678181881.

It is a happy number.

It is a self number, because there is not a number n which added to its sum of digits gives 18818187644.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (18818187649) 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, 242702 + ... + 310709.

It is an arithmetic number, because the mean of its divisors is an integer number (2744646814).

Almost surely, 2^18818187644 is an apocalyptic number.

It is an amenable number.

18818187644 is a deficient number, since it is larger than the sum of its proper divisors (14117574124).

18818187644 is a wasteful number, since it uses less digits than its factorization.

18818187644 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 561916 (or 561914 counting only the distinct ones).

The product of its digits is 2752512, while the sum is 56.

The spelling of 18818187644 in words is "eighteen billion, eight hundred eighteen million, one hundred eighty-seven thousand, six hundred forty-four".