8018721665856 has 672 divisors, whose sum is σ = 27003159421056. Its totient is φ = 2338025472000.

The previous prime is 8018721665837. The next prime is 8018721665917. The reversal of 8018721665856 is 6585661278108.

It is a Smith number, since the sum of its digits (63) coincides with the sum of the digits of its prime factors.

It is a junction number, because it is equal to n+sod(n) for n = 8018721665793 and 8018721665802.

It is a congruent number.

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 95 ways as a sum of consecutive naturals, for example, 512010666 + ... + 512026326.

It is an arithmetic number, because the mean of its divisors is an integer number (40183272948).

Almost surely, 2^{8018721665856} is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 8018721665856, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (13501579710528).

8018721665856 is an abundant number, since it is smaller than the sum of its proper divisors (18984437755200).

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

8018721665856 is a wasteful number, since it uses less digits than its factorization.

8018721665856 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 15813 (or 15791 counting only the distinct ones).

The product of its (nonzero) digits is 38707200, while the sum is 63.

The spelling of 8018721665856 in words is "eight trillion, eighteen billion, seven hundred twenty-one million, six hundred sixty-five thousand, eight hundred fifty-six".