21222404 has 12 divisors (see below), whose sum is σ = 42444864. Its totient is φ = 9095304.

The previous prime is 21222401. The next prime is 21222433. The reversal of 21222404 is 40422212.

It is a happy number.

21222404 is an admirable number.

It is not an unprimeable number, because it can be changed into a prime (21222401) 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, 378944 + ... + 378999.

It is an arithmetic number, because the mean of its divisors is an integer number (3537072).

Almost surely, 2^21222404 is an apocalyptic number.

It is an amenable number.

21222404 is a primitive abundant number, since it is smaller than the sum of its proper divisors, none of which is abundant.

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

21222404 is a wasteful number, since it uses less digits than its factorization.

21222404 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 757954 (or 757952 counting only the distinct ones).

The product of its (nonzero) digits is 256, while the sum is 17.

The square root of 21222404 is about 4606.7780497871. The cubic root of 21222404 is about 276.8629609693.

Adding to 21222404 its reverse (40422212), we get a palindrome (61644616).

The spelling of 21222404 in words is "twenty-one million, two hundred twenty-two thousand, four hundred four".