21563042 has 16 divisors (see below), whose sum is σ = 33530112. Its totient is φ = 10389360.

The previous prime is 21563041. The next prime is 21563051. The reversal of 21563042 is 24036512.

It is a junction number, because it is equal to n+sod(n) for n = 21562999 and 21563017.

It is not an unprimeable number, because it can be changed into a prime (21563041) 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, 17573 + ... + 18759.

It is an arithmetic number, because the mean of its divisors is an integer number (2095632).

Almost surely, 2^21563042 is an apocalyptic number.

21563042 is a deficient number, since it is larger than the sum of its proper divisors (11967070).

21563042 is a wasteful number, since it uses less digits than its factorization.

21563042 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1513.

The product of its (nonzero) digits is 1440, while the sum is 23.

The square root of 21563042 is about 4643.6022654831. The cubic root of 21563042 is about 278.3364024506.

Adding to 21563042 its reverse (24036512), we get a palindrome (45599554).

The spelling of 21563042 in words is "twenty-one million, five hundred sixty-three thousand, forty-two".