1638619891108 has 48 divisors (see below), whose sum is σ = 3013213271040. Its totient is φ = 778852174464.

The previous prime is 1638619891099. The next prime is 1638619891109. The reversal of 1638619891108 is 8011989168361.

It is not an unprimeable number, because it can be changed into a prime (1638619891109) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 1437685 + ... + 2311747.

It is an arithmetic number, because the mean of its divisors is an integer number (62775276480).

Almost surely, 2^{1638619891108} is an apocalyptic number.

It is an amenable number.

1638619891108 is a deficient number, since it is larger than the sum of its proper divisors (1374593379932).

1638619891108 is a wasteful number, since it uses less digits than its factorization.

1638619891108 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 874396 (or 874394 counting only the distinct ones).

The product of its (nonzero) digits is 4478976, while the sum is 61.

The spelling of 1638619891108 in words is "one trillion, six hundred thirty-eight billion, six hundred nineteen million, eight hundred ninety-one thousand, one hundred eight".