18909398197806 has 16 divisors (see below), whose sum is σ = 39038757570048. Its totient is φ = 6099805870200.

The previous prime is 18909398197777. The next prime is 18909398197829. The reversal of 18909398197806 is 60879189390981.

It is a congruent number.

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, 50831715400 + ... + 50831715771.

It is an arithmetic number, because the mean of its divisors is an integer number (2439922348128).

Almost surely, 2^{18909398197806} is an apocalyptic number.

18909398197806 is an abundant number, since it is smaller than the sum of its proper divisors (20129359372242).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

18909398197806 is a wasteful number, since it uses less digits than its factorization.

18909398197806 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 101663431207.

The product of its (nonzero) digits is 423263232, while the sum is 78.

The spelling of 18909398197806 in words is "eighteen trillion, nine hundred nine billion, three hundred ninety-eight million, one hundred ninety-seven thousand, eight hundred six".