21215336 has 16 divisors (see below), whose sum is σ = 40011300. Its totient is φ = 10545664.

The previous prime is 21215329. The next prime is 21215339. The reversal of 21215336 is 63351212.

It can be written as a sum of positive squares in 2 ways, for example, as 21215236 + 100 = 4606^2 + 10^2 .

It is not an unprimeable number, because it can be changed into a prime (21215339) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 6281 + ... + 9048.

Almost surely, 2^21215336 is an apocalyptic number.

It is an amenable number.

21215336 is a deficient number, since it is larger than the sum of its proper divisors (18795964).

21215336 is a wasteful number, since it uses less digits than its factorization.

21215336 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 15508 (or 15504 counting only the distinct ones).

The product of its digits is 1080, while the sum is 23.

The square root of 21215336 is about 4606.0108553932. The cubic root of 21215336 is about 276.8322216825.

Adding to 21215336 its reverse (63351212), we get a palindrome (84566548).

The spelling of 21215336 in words is "twenty-one million, two hundred fifteen thousand, three hundred thirty-six".