18421233738 has 16 divisors (see below), whose sum is σ = 38444314176. Its totient is φ = 5873436800.

The previous prime is 18421233731. The next prime is 18421233739. The reversal of 18421233738 is 83733212481.

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 18421233738.

It is not an unprimeable number, because it can be changed into a prime (18421233731) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 66743463 + ... + 66743738.

It is an arithmetic number, because the mean of its divisors is an integer number (2402769636).

Almost surely, 2^18421233738 is an apocalyptic number.

18421233738 is an abundant number, since it is smaller than the sum of its proper divisors (20023080438).

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

18421233738 is a wasteful number, since it uses less digits than its factorization.

18421233738 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 133487229.

The product of its digits is 193536, while the sum is 42.

The spelling of 18421233738 in words is "eighteen billion, four hundred twenty-one million, two hundred thirty-three thousand, seven hundred thirty-eight".