91287220 has 24 divisors (see below), whose sum is σ = 192138408. Its totient is φ = 36432000.

The previous prime is 91287199. The next prime is 91287223. The reversal of 91287220 is 2278219.

It can be written as a sum of positive squares in 4 ways, for example, as 22695696 + 68591524 = 4764^2 + 8282^2 .

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (91287223) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 4270 + ... + 14170.

It is an arithmetic number, because the mean of its divisors is an integer number (8005767).

Almost surely, 2^91287220 is an apocalyptic number.

It is an amenable number.

91287220 is an abundant number, since it is smaller than the sum of its proper divisors (100851188).

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

91287220 is a wasteful number, since it uses less digits than its factorization.

91287220 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 10371 (or 10369 counting only the distinct ones).

The product of its (nonzero) digits is 4032, while the sum is 31.

The square root of 91287220 is about 9554.4345724904. The cubic root of 91287220 is about 450.2668705089.

The spelling of 91287220 in words is "ninety-one million, two hundred eighty-seven thousand, two hundred twenty".