20563243 has 4 divisors (see below), whose sum is σ = 20711320. Its totient is φ = 20415168.

The previous prime is 20563237. The next prime is 20563259. The reversal of 20563243 is 34236502.

It is a happy number.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 34236502 = 2 ⋅17118251.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-20563243 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (20563343) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 73830 + ... + 74107.

It is an arithmetic number, because the mean of its divisors is an integer number (5177830).

Almost surely, 2^20563243 is an apocalyptic number.

20563243 is a deficient number, since it is larger than the sum of its proper divisors (148077).

20563243 is a wasteful number, since it uses less digits than its factorization.

20563243 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 148076.

The product of its (nonzero) digits is 4320, while the sum is 25.

The square root of 20563243 is about 4534.6712118962. The cubic root of 20563243 is about 273.9663366390.

Adding to 20563243 its reverse (34236502), we get a palindrome (54799745).

The spelling of 20563243 in words is "twenty million, five hundred sixty-three thousand, two hundred forty-three".