91771308720 has 800 divisors, whose sum is σ = 412986900480. Its totient is φ = 18341406720.

The previous prime is 91771308697. The next prime is 91771308751. The reversal of 91771308720 is 2780317719.

It is a Harshad number since it is a multiple of its sum of digits (45).

It is an unprimeable number.

It is a polite number, since it can be written in 159 ways as a sum of consecutive naturals, for example, 11199825 + ... + 11208015.

Almost surely, 2^91771308720 is an apocalyptic number.

91771308720 is a gapful number since it is divisible by the number (90) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 91771308720, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (206493450240).

91771308720 is an abundant number, since it is smaller than the sum of its proper divisors (321215591760).

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

91771308720 is a wasteful number, since it uses less digits than its factorization.

91771308720 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 8255 (or 8240 counting only the distinct ones).

The product of its (nonzero) digits is 148176, while the sum is 45.

The spelling of 91771308720 in words is "ninety-one billion, seven hundred seventy-one million, three hundred eight thousand, seven hundred twenty".