21225530 has 8 divisors (see below), whose sum is σ = 38205972. Its totient is φ = 8490208.

The previous prime is 21225511. The next prime is 21225541. The reversal of 21225530 is 3552212.

It can be written as a sum of positive squares in 2 ways, for example, as 17581249 + 3644281 = 4193^2 + 1909^2 .

It is a sphenic number, since it is the product of 3 distinct primes.

It is a Curzon number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1061267 + ... + 1061286.

Almost surely, 2^21225530 is an apocalyptic number.

21225530 is a deficient number, since it is larger than the sum of its proper divisors (16980442).

21225530 is a wasteful number, since it uses less digits than its factorization.

21225530 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2122560.

The product of its (nonzero) digits is 600, while the sum is 20.

The square root of 21225530 is about 4607.1173199735. The cubic root of 21225530 is about 276.8765540119.

Adding to 21225530 its reverse (3552212), we get a palindrome (24777742).

The spelling of 21225530 in words is "twenty-one million, two hundred twenty-five thousand, five hundred thirty".