91009100080 has 40 divisors (see below), whose sum is σ = 215182544400. Its totient is φ = 35786627328.

The previous prime is 91009100029. The next prime is 91009100087. The reversal of 91009100080 is 8000190019.

It is a tau number, because it is divible by the number of its divisors (40).

It is not an unprimeable number, because it can be changed into a prime (91009100087) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 9636075 + ... + 9645514.

It is an arithmetic number, because the mean of its divisors is an integer number (5379563610).

Almost surely, 2^91009100080 is an apocalyptic number.

It is an amenable number.

91009100080 is an abundant number, since it is smaller than the sum of its proper divisors (124173444320).

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

91009100080 is a wasteful number, since it uses less digits than its factorization.

91009100080 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 19281661 (or 19281655 counting only the distinct ones).

The product of its (nonzero) digits is 648, while the sum is 28.

Adding to 91009100080 its reverse (8000190019), we get a palindrome (99009290099).

The spelling of 91009100080 in words is "ninety-one billion, nine million, one hundred thousand, eighty".