91217140 has 48 divisors (see below), whose sum is σ = 221122944. Its totient is φ = 30960000.

The previous prime is 91217131. The next prime is 91217141. The reversal of 91217140 is 4171219.

91217140 is digitally balanced in base 9, because in such base it contains all the possibile digits an equal number of times.

91217140 is strictly pandigital in base 9.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (91217141) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 10915 + ... + 17365.

It is an arithmetic number, because the mean of its divisors is an integer number (4606728).

Almost surely, 2^91217140 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 91217140, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (110561472).

91217140 is an abundant number, since it is smaller than the sum of its proper divisors (129905804).

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

91217140 is a wasteful number, since it uses less digits than its factorization.

91217140 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 6568 (or 6566 counting only the distinct ones).

The product of its (nonzero) digits is 504, while the sum is 25.

The square root of 91217140 is about 9550.7664613894. The cubic root of 91217140 is about 450.1516196905.

Adding to 91217140 its reverse (4171219), we get a palindrome (95388359).

It can be divided in two parts, 9121 and 7140, that added together give a palindrome (16261).

The spelling of 91217140 in words is "ninety-one million, two hundred seventeen thousand, one hundred forty".