21131323224 has 32 divisors (see below), whose sum is σ = 57630882240. Its totient is φ = 6403431200.

The previous prime is 21131323223. The next prime is 21131323253. The reversal of 21131323224 is 42232313112.

It is a Harshad number since it is a multiple of its sum of digits (24).

It is a nude number because it is divisible by every one of its digits.

It is a junction number, because it is equal to n+sod(n) for n = 21131323194 and 21131323203.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21131323223) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 40021182 + ... + 40021709.

It is an arithmetic number, because the mean of its divisors is an integer number (1800965070).

Almost surely, 2^21131323224 is an apocalyptic number.

21131323224 is a gapful number since it is divisible by the number (24) formed by its first and last digit.

It is an amenable number.

21131323224 is an abundant number, since it is smaller than the sum of its proper divisors (36499559016).

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

21131323224 is a wasteful number, since it uses less digits than its factorization.

21131323224 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 80042911 (or 80042907 counting only the distinct ones).

The product of its digits is 1728, while the sum is 24.

Adding to 21131323224 its reverse (42232313112), we get a palindrome (63363636336).

The spelling of 21131323224 in words is "twenty-one billion, one hundred thirty-one million, three hundred twenty-three thousand, two hundred twenty-four".