91206640 has 120 divisors (see below), whose sum is σ = 251903520. Its totient is φ = 30610944.

The previous prime is 91206629. The next prime is 91206667. The reversal of 91206640 is 4660219.

It is a Harshad number since it is a multiple of its sum of digits (28).

It is a junction number, because it is equal to n+sod(n) for n = 91206599 and 91206608.

It is a congruent number.

It is an unprimeable number.

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 23 ways as a sum of consecutive naturals, for example, 207541 + ... + 207979.

It is an arithmetic number, because the mean of its divisors is an integer number (2099196).

Almost surely, 2^91206640 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 91206640, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (125951760).

91206640 is an abundant number, since it is smaller than the sum of its proper divisors (160696880).

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

91206640 is a wasteful number, since it uses less digits than its factorization.

91206640 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 519 (or 506 counting only the distinct ones).

The product of its (nonzero) digits is 2592, while the sum is 28.

The square root of 91206640 is about 9550.2167514670. The cubic root of 91206640 is about 450.1343467183.

Adding to 91206640 its reverse (4660219), we get a palindrome (95866859).

The spelling of 91206640 in words is "ninety-one million, two hundred six thousand, six hundred forty".