91721325612 has 144 divisors (see below), whose sum is σ = 255283902720. Its totient is φ = 25542776448.

The previous prime is 91721325593. The next prime is 91721325673. The reversal of 91721325612 is 21652312719.

It is an unprimeable number.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 12865993 + ... + 12873119.

It is an arithmetic number, because the mean of its divisors is an integer number (1772804880).

Almost surely, 2^91721325612 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 91721325612, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (127641951360).

91721325612 is an abundant number, since it is smaller than the sum of its proper divisors (163562577108).

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

91721325612 is a wasteful number, since it uses less digits than its factorization.

91721325612 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 7700 (or 7691 counting only the distinct ones).

The product of its digits is 45360, while the sum is 39.

The spelling of 91721325612 in words is "ninety-one billion, seven hundred twenty-one million, three hundred twenty-five thousand, six hundred twelve".