21225318 has 16 divisors (see below), whose sum is σ = 44685120. Its totient is φ = 6702696.

The previous prime is 21225317. The next prime is 21225329. The reversal of 21225318 is 81352212.

It is a super-2 number, since 2×21225318² = 901028248402248, which contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21225311) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 92980 + ... + 93207.

It is an arithmetic number, because the mean of its divisors is an integer number (2792820).

Almost surely, 2^21225318 is an apocalyptic number.

21225318 is an abundant number, since it is smaller than the sum of its proper divisors (23459802).

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

21225318 is a wasteful number, since it uses less digits than its factorization.

21225318 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 186211.

The product of its digits is 960, while the sum is 24.

The square root of 21225318 is about 4607.0943120366. The cubic root of 21225318 is about 276.8756321971.

The spelling of 21225318 in words is "twenty-one million, two hundred twenty-five thousand, three hundred eighteen".