11823221538 has 30 divisors (see below), whose sum is σ = 26495875659. Its totient is φ = 3940612524.

The previous prime is 11823221513. The next prime is 11823221539. The reversal of 11823221538 is 83512232811.

11823221538 is a `hidden beast` number, since 1 + 182 + 322 + 153 + 8 = 666.

It can be written as a sum of positive squares in only one way, i.e., 5911610769 + 5911610769 = 76887^2 + 76887^2 .

It is an ABA number since it can be written as A⋅B^A, here for A=2, B=76887.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (11823221539) by changing a digit.

It is a polite number, since it can be written in 14 ways as a sum of consecutive naturals, for example, 1379695 + ... + 1388237.

Almost surely, 2^11823221538 is an apocalyptic number.

11823221538 is a gapful number since it is divisible by the number (18) formed by its first and last digit.

11823221538 is an abundant number, since it is smaller than the sum of its proper divisors (14672654121).

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

11823221538 is an frugal number, since it uses more digits than its factorization.

11823221538 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 17100 (or 8548 counting only the distinct ones).

The product of its digits is 23040, while the sum is 36.

The spelling of 11823221538 in words is "eleven billion, eight hundred twenty-three million, two hundred twenty-one thousand, five hundred thirty-eight".