91985067720 has 640 divisors, whose sum is σ = 388346112000. Its totient is φ = 19404790272.

The previous prime is 91985067701. The next prime is 91985067721. The reversal of 91985067720 is 2776058919.

It is a super-2 number, since 2×91985067720² (a number of 23 digits) contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (54).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (91985067721) by changing a digit.

It is a polite number, since it can be written in 159 ways as a sum of consecutive naturals, for example, 14443977 + ... + 14450343.

It is an arithmetic number, because the mean of its divisors is an integer number (606790800).

Almost surely, 2^91985067720 is an apocalyptic number.

91985067720 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 91985067720, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (194173056000).

91985067720 is an abundant number, since it is smaller than the sum of its proper divisors (296361044280).

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

91985067720 is a wasteful number, since it uses less digits than its factorization.

91985067720 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 6424 (or 6397 counting only the distinct ones).

The product of its (nonzero) digits is 1905120, while the sum is 54.

The spelling of 91985067720 in words is "ninety-one billion, nine hundred eighty-five million, sixty-seven thousand, seven hundred twenty".