91640 has 32 divisors (see below), whose sum is σ = 216000. Its totient is φ = 34944.

The previous prime is 91639. The next prime is 91673. The reversal of 91640 is 4619.

It is a Harshad number since it is a multiple of its sum of digits (20).

It is a plaindrome in base 14.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 1121 + ... + 1199.

It is an arithmetic number, because the mean of its divisors is an integer number (6750).

2⁹¹⁶⁴⁰ is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 91640, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (108000).

91640 is an abundant number, since it is smaller than the sum of its proper divisors (124360).

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

91640 is a wasteful number, since it uses less digits than its factorization.

91640 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 119 (or 115 counting only the distinct ones).

The product of its (nonzero) digits is 216, while the sum is 20.

The square root of 91640 is about 302.7209936559. The cubic root of 91640 is about 45.0846144605.

The spelling of 91640 in words is "ninety-one thousand, six hundred forty".