91000080 has 120 divisors (see below), whose sum is σ = 307569600. Its totient is φ = 24111360.

The previous prime is 91000051. The next prime is 91000081. The reversal of 91000080 is 8000019.

It is a tau number, because it is divible by the number of its divisors (120).

It is a Harshad number since it is a multiple of its sum of digits (18).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (91000081) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 151621 + ... + 152219.

It is an arithmetic number, because the mean of its divisors is an integer number (2563080).

Almost surely, 2^91000080 is an apocalyptic number.

91000080 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 91000080, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (153784800).

91000080 is an abundant number, since it is smaller than the sum of its proper divisors (216569520).

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

91000080 is a wasteful number, since it uses less digits than its factorization.

91000080 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 829 (or 820 counting only the distinct ones).

The product of its (nonzero) digits is 72, while the sum is 18.

The square root of 91000080 is about 9539.3962073079. The cubic root of 91000080 is about 449.7942763353.

Adding to 91000080 its reverse (8000019), we get a palindrome (99000099).

The spelling of 91000080 in words is "ninety-one million, eighty", and thus it is an aban number and an uban number.