21223136 has 24 divisors (see below), whose sum is σ = 45582264. Its totient is φ = 9646720.

The previous prime is 21223093. The next prime is 21223141. The reversal of 21223136 is 63132212.

It is a happy number.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 29795 + ... + 30498.

It is an arithmetic number, because the mean of its divisors is an integer number (1899261).

Almost surely, 2^21223136 is an apocalyptic number.

It is an amenable number.

21223136 is an abundant number, since it is smaller than the sum of its proper divisors (24359128).

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

21223136 is a wasteful number, since it uses less digits than its factorization.

21223136 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 60314 (or 60306 counting only the distinct ones).

The product of its digits is 432, while the sum is 20.

The square root of 21223136 is about 4606.8574972534. The cubic root of 21223136 is about 276.8661441047.

Adding to 21223136 its reverse (63132212), we get a palindrome (84355348).

The spelling of 21223136 in words is "twenty-one million, two hundred twenty-three thousand, one hundred thirty-six".