1638138180438 has 24 divisors (see below), whose sum is σ = 3549561802488. Its totient is φ = 546005689152.

The previous prime is 1638138180407. The next prime is 1638138180439. The reversal of 1638138180438 is 8340818318361.

It is a happy number.

1638138180438 is a `hidden beast` number, since 1 + 63 + 8 + 138 + 18 + 0 + 438 = 666.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1638138180439) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 3113520 + ... + 3601427.

It is an arithmetic number, because the mean of its divisors is an integer number (147898408437).

Almost surely, 2^{1638138180438} is an apocalyptic number.

1638138180438 is a gapful number since it is divisible by the number (18) formed by its first and last digit.

1638138180438 is an abundant number, since it is smaller than the sum of its proper divisors (1911423622050).

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

1638138180438 is a wasteful number, since it uses less digits than its factorization.

1638138180438 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 6728508 (or 6728505 counting only the distinct ones).

The product of its (nonzero) digits is 2654208, while the sum is 54.

The spelling of 1638138180438 in words is "one trillion, six hundred thirty-eight billion, one hundred thirty-eight million, one hundred eighty thousand, four hundred thirty-eight".