91121550 has 96 divisors (see below), whose sum is σ = 246734208. Its totient is φ = 22120320.

The previous prime is 91121533. The next prime is 91121551. The reversal of 91121550 is 5512119.

It is a super-3 number, since 3×91121550³ (a number of 25 digits) contains 333 as substring.

It is a self number, because there is not a number n which added to its sum of digits gives 91121550.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (91121551) by changing a digit.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 161569 + ... + 162131.

It is an arithmetic number, because the mean of its divisors is an integer number (2570148).

Almost surely, 2^91121550 is an apocalyptic number.

It is a practical number, because each smaller number is the sum of distinct divisors of 91121550, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (123367104).

91121550 is an abundant number, since it is smaller than the sum of its proper divisors (155612658).

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

91121550 is a wasteful number, since it uses less digits than its factorization.

91121550 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 674 (or 669 counting only the distinct ones).

The product of its (nonzero) digits is 450, while the sum is 24.

The square root of 91121550 is about 9545.7608392417. The cubic root of 91121550 is about 449.9943209160.

Adding to 91121550 its reverse (5512119), we get a palindrome (96633669).

The spelling of 91121550 in words is "ninety-one million, one hundred twenty-one thousand, five hundred fifty".