1981717286918 has 64 divisors (see below), whose sum is σ = 3190763778048. Its totient is φ = 921903016320.

The previous prime is 1981717286741. The next prime is 1981717286947. The reversal of 1981717286918 is 8196827171891.

It is a happy number.

It is a Curzon number.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 20312771 + ... + 20410097.

It is an arithmetic number, because the mean of its divisors is an integer number (49855684032).

Almost surely, 2^{1981717286918} is an apocalyptic number.

1981717286918 is a deficient number, since it is larger than the sum of its proper divisors (1209046491130).

1981717286918 is a wasteful number, since it uses less digits than its factorization.

1981717286918 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 97557.

The product of its digits is 24385536, while the sum is 68.

The spelling of 1981717286918 in words is "one trillion, nine hundred eighty-one billion, seven hundred seventeen million, two hundred eighty-six thousand, nine hundred eighteen".