71991700128 has 96 divisors (see below), whose sum is σ = 210917952000. Its totient is φ = 23889558528.

The previous prime is 71991700127. The next prime is 71991700141. The reversal of 71991700128 is 82100719917.

It is a happy number.

It is a tau number, because it is divible by the number of its divisors (96).

It is not an unprimeable number, because it can be changed into a prime (71991700127) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 5848 + ... + 379496.

It is an arithmetic number, because the mean of its divisors is an integer number (2197062000).

Almost surely, 2^71991700128 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 71991700128, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (105458976000).

71991700128 is an abundant number, since it is smaller than the sum of its proper divisors (138926251872).

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

71991700128 is a wasteful number, since it uses less digits than its factorization.

71991700128 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 373891 (or 373877 counting only the distinct ones).

The product of its (nonzero) digits is 63504, while the sum is 45.

The spelling of 71991700128 in words is "seventy-one billion, nine hundred ninety-one million, seven hundred thousand, one hundred twenty-eight".