21563312 has 10 divisors (see below), whose sum is σ = 41778948. Its totient is φ = 10781648.

The previous prime is 21563303. The next prime is 21563329. The reversal of 21563312 is 21336512.

It is an unprimeable number.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 673838 + ... + 673869.

Almost surely, 2^21563312 is an apocalyptic number.

It is an amenable number.

21563312 is a deficient number, since it is larger than the sum of its proper divisors (20215636).

21563312 is a wasteful number, since it uses less digits than its factorization.

21563312 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1347715 (or 1347709 counting only the distinct ones).

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

The square root of 21563312 is about 4643.6313376494. The cubic root of 21563312 is about 278.3375641685.

Adding to 21563312 its reverse (21336512), we get a palindrome (42899824).

The spelling of 21563312 in words is "twenty-one million, five hundred sixty-three thousand, three hundred twelve".