21530222 has 16 divisors (see below), whose sum is σ = 37052640. Its totient is φ = 9191328.

The previous prime is 21530161. The next prime is 21530227. The reversal of 21530222 is 22203512.

It is a self number, because there is not a number n which added to its sum of digits gives 21530222.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21530227) by changing a digit.

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 7 ways as a sum of consecutive naturals, for example, 908 + ... + 6624.

It is an arithmetic number, because the mean of its divisors is an integer number (2315790).

Almost surely, 2^21530222 is an apocalyptic number.

21530222 is a deficient number, since it is larger than the sum of its proper divisors (15522418).

21530222 is a wasteful number, since it uses less digits than its factorization.

21530222 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5995.

The product of its (nonzero) digits is 240, while the sum is 17.

The square root of 21530222 is about 4640.0670253780. The cubic root of 21530222 is about 278.1951168922.

Adding to 21530222 its reverse (22203512), we get a palindrome (43733734).

The spelling of 21530222 in words is "twenty-one million, five hundred thirty thousand, two hundred twenty-two".