21563452 has 24 divisors (see below), whose sum is σ = 38959424. Its totient is φ = 10435392.

The previous prime is 21563449. The next prime is 21563453. The reversal of 21563452 is 25436512.

It is a self number, because there is not a number n which added to its sum of digits gives 21563452.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21563453) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 54118 + ... + 54514.

Almost surely, 2^21563452 is an apocalyptic number.

It is an amenable number.

21563452 is a deficient number, since it is larger than the sum of its proper divisors (17395972).

21563452 is a wasteful number, since it uses less digits than its factorization.

21563452 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 805 (or 803 counting only the distinct ones).

The product of its digits is 7200, while the sum is 28.

The square root of 21563452 is about 4643.6464120344. The cubic root of 21563452 is about 278.3381665369.

Adding to 21563452 its reverse (25436512), we get a palindrome (46999964).

The spelling of 21563452 in words is "twenty-one million, five hundred sixty-three thousand, four hundred fifty-two".