91684440 has 128 divisors (see below), whose sum is σ = 318988800. Its totient is φ = 23379840.

The previous prime is 91684421. The next prime is 91684447. The reversal of 91684440 is 4448619.

It is a happy number.

It is a super-2 number, since 2×91684440² = 16812073076227200, which contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (36).

It is a junction number, because it is equal to n+sod(n) for n = 91684395 and 91684404.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (91684447) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 22995 + ... + 26685.

It is an arithmetic number, because the mean of its divisors is an integer number (2492100).

Almost surely, 2^91684440 is an apocalyptic number.

91684440 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 91684440, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (159494400).

91684440 is an abundant number, since it is smaller than the sum of its proper divisors (227304360).

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

91684440 is a wasteful number, since it uses less digits than its factorization.

91684440 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3734 (or 3724 counting only the distinct ones).

The product of its (nonzero) digits is 27648, while the sum is 36.

The square root of 91684440 is about 9575.1992146378. The cubic root of 91684440 is about 450.9190107650.

The spelling of 91684440 in words is "ninety-one million, six hundred eighty-four thousand, four hundred forty".