21563045 has 16 divisors (see below), whose sum is σ = 30373248. Its totient is φ = 14385600.

The previous prime is 21563041. The next prime is 21563051. The reversal of 21563045 is 54036512.

It is not a de Polignac number, because 21563045 - 2² = 21563041 is a prime.

It is a Duffinian number.

It is a congruent number.

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 15 ways as a sum of consecutive naturals, for example, 7031 + ... + 9620.

It is an arithmetic number, because the mean of its divisors is an integer number (1898328).

Almost surely, 2^21563045 is an apocalyptic number.

It is an amenable number.

21563045 is a deficient number, since it is larger than the sum of its proper divisors (8810203).

21563045 is a wasteful number, since it uses less digits than its factorization.

21563045 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 16700.

The product of its (nonzero) digits is 3600, while the sum is 26.

The square root of 21563045 is about 4643.6025885082. The cubic root of 21563045 is about 278.3364153586.

Adding to 21563045 its reverse (54036512), we get a palindrome (75599557).

The spelling of 21563045 in words is "twenty-one million, five hundred sixty-three thousand, forty-five".