21152221224 has 16 divisors (see below), whose sum is σ = 52880553120. Its totient is φ = 7050740400.

The previous prime is 21152221199. The next prime is 21152221229. The reversal of 21152221224 is 42212225112.

It is a happy number.

It is a Harshad number since it is a multiple of its sum of digits (24), and also a Moran number because the ratio is a prime number: 881342551 = 21152221224 / (2 + 1 + 1 + 5 + 2 + 2 + 2 + 1 + 2 + 2 + 4).

It is a junction number, because it is equal to n+sod(n) for n = 21152221194 and 21152221203.

It is not an unprimeable number, because it can be changed into a prime (21152221229) 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, 440671252 + ... + 440671299.

It is an arithmetic number, because the mean of its divisors is an integer number (3305034570).

Almost surely, 2^21152221224 is an apocalyptic number.

21152221224 is a gapful number since it is divisible by the number (24) formed by its first and last digit.

It is an amenable number.

21152221224 is an abundant number, since it is smaller than the sum of its proper divisors (31728331896).

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

21152221224 is a wasteful number, since it uses less digits than its factorization.

21152221224 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 881342560 (or 881342556 counting only the distinct ones).

The product of its digits is 1280, while the sum is 24.

Adding to 21152221224 its reverse (42212225112), we get a palindrome (63364446336).

The spelling of 21152221224 in words is "twenty-one billion, one hundred fifty-two million, two hundred twenty-one thousand, two hundred twenty-four".