1638138123 has 6 divisors (see below), whose sum is σ = 2366199524. Its totient is φ = 1092092076.

The previous prime is 1638138097. The next prime is 1638138133. The reversal of 1638138123 is 3218318361.

1638138123 is a `hidden beast` number, since 1 + 638 + 1 + 3 + 8 + 12 + 3 = 666.

It is not a de Polignac number, because 1638138123 - 2⁵ = 1638138091 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (1638138133) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 91007665 + ... + 91007682.

Almost surely, 2^1638138123 is an apocalyptic number.

1638138123 is a deficient number, since it is larger than the sum of its proper divisors (728061401).

1638138123 is a wasteful number, since it uses less digits than its factorization.

1638138123 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 182015353 (or 182015350 counting only the distinct ones).

The product of its digits is 20736, while the sum is 36.

The square root of 1638138123 is about 40473.9190467145. The cubic root of 1638138123 is about 1178.8272661194.

The spelling of 1638138123 in words is "one billion, six hundred thirty-eight million, one hundred thirty-eight thousand, one hundred twenty-three".