19808318818 has 16 divisors (see below), whose sum is σ = 30244566456. Its totient is φ = 9727280640.

The previous prime is 19808318801. The next prime is 19808318851. The reversal of 19808318818 is 81881380891.

It can be written as a sum of positive squares in 4 ways, for example, as 13076608609 + 6731710209 = 114353^2 + 82047^2 .

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 38521 + ... + 202732.

Almost surely, 2^19808318818 is an apocalyptic number.

19808318818 is a deficient number, since it is larger than the sum of its proper divisors (10436247638).

19808318818 is a wasteful number, since it uses less digits than its factorization.

19808318818 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 241989.

The product of its (nonzero) digits is 884736, while the sum is 55.

The spelling of 19808318818 in words is "nineteen billion, eight hundred eight million, three hundred eighteen thousand, eight hundred eighteen".