71991881809920 has 600 divisors, whose sum is σ = 262967378479344. Its totient is φ = 18835519832064.

The previous prime is 71991881809907. The next prime is 71991881809957. The reversal of 71991881809920 is 2990818819917.

It is a Harshad number since it is a multiple of its sum of digits (72).

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 39 ways as a sum of consecutive naturals, for example, 351580207 + ... + 351784913.

Almost surely, 2^{71991881809920} 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 71991881809920, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (131483689239672).

71991881809920 is an abundant number, since it is smaller than the sum of its proper divisors (190975496669424).

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

71991881809920 is an equidigital number, since it uses as much as digits as its factorization.

71991881809920 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 204805 (or 204770 counting only the distinct ones).

The product of its (nonzero) digits is 47029248, while the sum is 72.

The spelling of 71991881809920 in words is "seventy-one trillion, nine hundred ninety-one billion, eight hundred eighty-one million, eight hundred nine thousand, nine hundred twenty".