1638489818 has 32 divisors (see below), whose sum is σ = 3014838144. Its totient is φ = 651843072.

The previous prime is 1638489799. The next prime is 1638489857. The reversal of 1638489818 is 8189848361.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 29780 + ... + 64527.

It is an arithmetic number, because the mean of its divisors is an integer number (94213692).

Almost surely, 2^1638489818 is an apocalyptic number.

1638489818 is a deficient number, since it is larger than the sum of its proper divisors (1376348326).

1638489818 is a wasteful number, since it uses less digits than its factorization.

1638489818 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 94406.

The product of its digits is 2654208, while the sum is 56.

The square root of 1638489818 is about 40478.2635250081. The cubic root of 1638489818 is about 1178.9116216414.

The spelling of 1638489818 in words is "one billion, six hundred thirty-eight million, four hundred eighty-nine thousand, eight hundred eighteen".