21236568 has 16 divisors (see below), whose sum is σ = 53091480. Its totient is φ = 7078848.

The previous prime is 21236561. The next prime is 21236569. The reversal of 21236568 is 86563212.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21236561) 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, 442405 + ... + 442452.

Almost surely, 2^21236568 is an apocalyptic number.

It is an amenable number.

21236568 is an abundant number, since it is smaller than the sum of its proper divisors (31854912).

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

21236568 is a wasteful number, since it uses less digits than its factorization.

21236568 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 884866 (or 884862 counting only the distinct ones).

The product of its digits is 17280, while the sum is 33.

The square root of 21236568 is about 4608.3150933937. The cubic root of 21236568 is about 276.9245407805.

The spelling of 21236568 in words is "twenty-one million, two hundred thirty-six thousand, five hundred sixty-eight".