91020 has 48 divisors (see below), whose sum is σ = 268128. Its totient is φ = 23040.

The previous prime is 91019. The next prime is 91033. The reversal of 91020 is 2019.

It is a happy number.

91020 is nontrivially palindromic in base 11.

It is a Harshad number since it is a multiple of its sum of digits (12).

It is a junction number, because it is equal to n+sod(n) for n = 90987 and 91005.

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, 2200 + ... + 2240.

It is an arithmetic number, because the mean of its divisors is an integer number (5586).

2⁹¹⁰²⁰ 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 91020, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (134064).

91020 is an abundant number, since it is smaller than the sum of its proper divisors (177108).

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

91020 is a wasteful number, since it uses less digits than its factorization.

91020 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 90 (or 88 counting only the distinct ones).

The product of its (nonzero) digits is 18, while the sum is 12.

The square root of 91020 is about 301.6952104360. The cubic root of 91020 is about 44.9827094066.

Adding to 91020 its reverse (2019), we get a palindrome (93039).

It can be divided in two parts, 9 and 1020, that multiplied together give a triangular number (9180 = T₁₃₅).

The spelling of 91020 in words is "ninety-one thousand, twenty".