91009840 has 40 divisors (see below), whose sum is σ = 224048160. Its totient is φ = 34262016.

The previous prime is 91009837. The next prime is 91009889. The reversal of 91009840 is 4890019.

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

It is an unprimeable number.

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, 32100 + ... + 34819.

It is an arithmetic number, because the mean of its divisors is an integer number (5601204).

Almost surely, 2^91009840 is an apocalyptic number.

It is an amenable number.

91009840 is an abundant number, since it is smaller than the sum of its proper divisors (133038320).

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

91009840 is a wasteful number, since it uses less digits than its factorization.

91009840 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 66949 (or 66943 counting only the distinct ones).

The product of its (nonzero) digits is 2592, while the sum is 31.

The square root of 91009840 is about 9539.9077563675. The cubic root of 91009840 is about 449.8103563036.

Adding to 91009840 its reverse (4890019), we get a palindrome (95899859).

The spelling of 91009840 in words is "ninety-one million, nine thousand, eight hundred forty".