91215240 has 64 divisors (see below), whose sum is σ = 285552000. Its totient is φ = 23265792.

The previous prime is 91215209. The next prime is 91215287. The reversal of 91215240 is 4251219.

It is a Harshad number since it is a multiple of its sum of digits (24).

It is a self number, because there is not a number n which added to its sum of digits gives 91215240.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 13765 + ... + 19284.

It is an arithmetic number, because the mean of its divisors is an integer number (4461750).

Almost surely, 2^91215240 is an apocalyptic number.

It is an amenable number.

91215240 is an abundant number, since it is smaller than the sum of its proper divisors (194336760).

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

91215240 is a wasteful number, since it uses less digits than its factorization.

91215240 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 33086 (or 33082 counting only the distinct ones).

The product of its (nonzero) digits is 720, while the sum is 24.

The square root of 91215240 is about 9550.6669924147. Note that the first 3 decimals coincide. The cubic root of 91215240 is about 450.1484942033.

Adding to 91215240 its reverse (4251219), we get a palindrome (95466459).

The spelling of 91215240 in words is "ninety-one million, two hundred fifteen thousand, two hundred forty".