1638619891099 has 2 divisors, whose sum is σ = 1638619891100. Its totient is φ = 1638619891098.

The previous prime is 1638619891091. The next prime is 1638619891109. The reversal of 1638619891099 is 9901989168361.

It is a happy number.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 1638619891099 - 2³ = 1638619891091 is a prime.

It is not a weakly prime, because it can be changed into another prime (1638619891091) 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 as a sum of consecutive naturals, namely, 819309945549 + 819309945550.

It is an arithmetic number, because the mean of its divisors is an integer number (819309945550).

Almost surely, 2^{1638619891099} is an apocalyptic number.

1638619891099 is a deficient number, since it is larger than the sum of its proper divisors (1).

1638619891099 is an equidigital number, since it uses as much as digits as its factorization.

1638619891099 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 45349632, while the sum is 70.

The spelling of 1638619891099 in words is "one trillion, six hundred thirty-eight billion, six hundred nineteen million, eight hundred ninety-one thousand, ninety-nine".