21224530 has 16 divisors (see below), whose sum is σ = 38331864. Its totient is φ = 8461440.

The previous prime is 21224521. The next prime is 21224557. The reversal of 21224530 is 3542212.

It can be written as a sum of positive squares in 4 ways, for example, as 9259849 + 11964681 = 3043^2 + 3459^2 .

It is a junction number, because it is equal to n+sod(n) for n = 21224498 and 21224507.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 261 + ... + 6520.

Almost surely, 2^21224530 is an apocalyptic number.

21224530 is a deficient number, since it is larger than the sum of its proper divisors (17107334).

21224530 is a wasteful number, since it uses less digits than its factorization.

21224530 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 7101.

The product of its (nonzero) digits is 480, while the sum is 19.

The square root of 21224530 is about 4607.0087909619. The cubic root of 21224530 is about 276.8722057750.

Adding to 21224530 its reverse (3542212), we get a palindrome (24766742).

It can be divided in two parts, 212 and 24530, that added together give a palindrome (24742).

The spelling of 21224530 in words is "twenty-one million, two hundred twenty-four thousand, five hundred thirty".