91181010820 has 12 divisors (see below), whose sum is σ = 191480122764. Its totient is φ = 36472404320.

The previous prime is 91181010797. The next prime is 91181010821. The reversal of 91181010820 is 2801018119.

It can be written as a sum of positive squares in 2 ways, for example, as 49120743424 + 42060267396 = 221632^2 + 205086^2 .

It is not an unprimeable number, because it can be changed into a prime (91181010821) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 2279525251 + ... + 2279525290.

It is an arithmetic number, because the mean of its divisors is an integer number (15956676897).

Almost surely, 2^91181010820 is an apocalyptic number.

It is an amenable number.

91181010820 is an abundant number, since it is smaller than the sum of its proper divisors (100299111944).

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

91181010820 is a wasteful number, since it uses less digits than its factorization.

91181010820 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4559050550 (or 4559050548 counting only the distinct ones).

The product of its (nonzero) digits is 1152, while the sum is 31.

Adding to 91181010820 its reverse (2801018119), we get a palindrome (93982028939).

The spelling of 91181010820 in words is "ninety-one billion, one hundred eighty-one million, ten thousand, eight hundred twenty".