1638815000138 has 4 divisors (see below), whose sum is σ = 2458222500210. Its totient is φ = 819407500068.

The previous prime is 1638815000111. The next prime is 1638815000149. The reversal of 1638815000138 is 8310005188361.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in only one way, i.e., 1266113297089 + 372701703049 = 1125217^2 + 610493^2 .

It is an unprimeable number.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 409703750033 + ... + 409703750036.

Almost surely, 2^{1638815000138} is an apocalyptic number.

1638815000138 is a deficient number, since it is larger than the sum of its proper divisors (819407500072).

1638815000138 is an equidigital number, since it uses as much as digits as its factorization.

1638815000138 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 819407500071.

The product of its (nonzero) digits is 138240, while the sum is 44.

The spelling of 1638815000138 in words is "one trillion, six hundred thirty-eight billion, eight hundred fifteen million, one hundred thirty-eight", and thus it is an aban number.