20145563 has 4 divisors (see below), whose sum is σ = 20574240. Its totient is φ = 19716888.

The previous prime is 20145557. The next prime is 20145571. The reversal of 20145563 is 36554102.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 20145563 - 2⁴ = 20145547 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (20145583) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 214268 + ... + 214361.

It is an arithmetic number, because the mean of its divisors is an integer number (5143560).

Almost surely, 2^20145563 is an apocalyptic number.

20145563 is a deficient number, since it is larger than the sum of its proper divisors (428677).

20145563 is an equidigital number, since it uses as much as digits as its factorization.

20145563 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 428676.

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

The square root of 20145563 is about 4488.3808884719. The cubic root of 20145563 is about 272.0987017442.

Adding to 20145563 its reverse (36554102), we get a palindrome (56699665).

The spelling of 20145563 in words is "twenty million, one hundred forty-five thousand, five hundred sixty-three".