21563332 has 18 divisors (see below), whose sum is σ = 43897182. Its totient is φ = 9241344.

The previous prime is 21563329. The next prime is 21563363. The reversal of 21563332 is 23336512.

It is a happy number.

It can be written as a sum of positive squares in only one way, i.e., 20575296 + 988036 = 4536^2 + 994^2 .

It is a junction number, because it is equal to n+sod(n) for n = 21563297 and 21563306.

It is an unprimeable number.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 54813 + ... + 55204.

Almost surely, 2^21563332 is an apocalyptic number.

It is an amenable number.

21563332 is an abundant number, since it is smaller than the sum of its proper divisors (22333850).

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

21563332 is a wasteful number, since it uses less digits than its factorization.

21563332 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 110035 (or 110026 counting only the distinct ones).

The product of its digits is 3240, while the sum is 25.

The square root of 21563332 is about 4643.6334911360. The cubic root of 21563332 is about 278.3376502213.

Adding to 21563332 its reverse (23336512), we get a palindrome (44899844).

The spelling of 21563332 in words is "twenty-one million, five hundred sixty-three thousand, three hundred thirty-two".