21225404 has 12 divisors (see below), whose sum is σ = 37615200. Its totient is φ = 10478208.

The previous prime is 21225403. The next prime is 21225431. The reversal of 21225404 is 40452212.

It is a happy number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21225403) 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, 33269 + ... + 33900.

It is an arithmetic number, because the mean of its divisors is an integer number (3134600).

Almost surely, 2^21225404 is an apocalyptic number.

It is an amenable number.

21225404 is a deficient number, since it is larger than the sum of its proper divisors (16389796).

21225404 is a wasteful number, since it uses less digits than its factorization.

21225404 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 67252 (or 67250 counting only the distinct ones).

The product of its (nonzero) digits is 640, while the sum is 20.

The square root of 21225404 is about 4607.1036454588. The cubic root of 21225404 is about 276.8760061416.

Adding to 21225404 its reverse (40452212), we get a palindrome (61677616).

The spelling of 21225404 in words is "twenty-one million, two hundred twenty-five thousand, four hundred four".