91811020 has 96 divisors (see below), whose sum is σ = 229211136. Its totient is φ = 30240000.

The previous prime is 91811017. The next prime is 91811051. The reversal of 91811020 is 2011819.

It is a junction number, because it is equal to n+sod(n) for n = 91810982 and 91811000.

It is an unprimeable number.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 607945 + ... + 608095.

It is an arithmetic number, because the mean of its divisors is an integer number (2387616).

Almost surely, 2^91811020 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 91811020, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (114605568).

91811020 is an abundant number, since it is smaller than the sum of its proper divisors (137400116).

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

91811020 is a wasteful number, since it uses less digits than its factorization.

91811020 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 311 (or 309 counting only the distinct ones).

The product of its (nonzero) digits is 144, while the sum is 22.

The square root of 91811020 is about 9581.8067189857. The cubic root of 91811020 is about 451.1264290264.

Adding to 91811020 its reverse (2011819), we get a palindrome (93822839).

It can be divided in two parts, 9181 and 1020, that added together give a palindrome (10201).

The spelling of 91811020 in words is "ninety-one million, eight hundred eleven thousand, twenty".