21135224 has 16 divisors (see below), whose sum is σ = 43231320. Its totient is φ = 9606880.

The previous prime is 21135223. The next prime is 21135227. The reversal of 21135224 is 42253112.

It is a junction number, because it is equal to n+sod(n) for n = 21135196 and 21135205.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21135223) 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, 119999 + ... + 120174.

Almost surely, 2^21135224 is an apocalyptic number.

It is an amenable number.

21135224 is an abundant number, since it is smaller than the sum of its proper divisors (22096096).

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

21135224 is a wasteful number, since it uses less digits than its factorization.

21135224 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 240190 (or 240186 counting only the distinct ones).

The product of its digits is 480, while the sum is 20.

The square root of 21135224 is about 4597.3061677465. The cubic root of 21135224 is about 276.4833300938.

Adding to 21135224 its reverse (42253112), we get a palindrome (63388336).

It can be divided in two parts, 2113 and 5224, that added together give a palindrome (7337).

The spelling of 21135224 in words is "twenty-one million, one hundred thirty-five thousand, two hundred twenty-four".