21344236 has 12 divisors (see below), whose sum is σ = 37432528. Its totient is φ = 10649232.

The previous prime is 21344209. The next prime is 21344237. The reversal of 21344236 is 63244312.

It is a self number, because there is not a number n which added to its sum of digits gives 21344236.

It is not an unprimeable number, because it can be changed into a prime (21344237) 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, 3531 + ... + 7426.

Almost surely, 2^21344236 is an apocalyptic number.

It is an amenable number.

21344236 is a deficient number, since it is larger than the sum of its proper divisors (16088292).

21344236 is a wasteful number, since it uses less digits than its factorization.

21344236 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 11448 (or 11446 counting only the distinct ones).

The product of its digits is 3456, while the sum is 25.

The square root of 21344236 is about 4619.9822510482. The cubic root of 21344236 is about 277.3917484867.

Adding to 21344236 its reverse (63244312), we get a palindrome (84588548).

The spelling of 21344236 in words is "twenty-one million, three hundred forty-four thousand, two hundred thirty-six".