20019563 has 4 divisors (see below), whose sum is σ = 20064600. Its totient is φ = 19974528.

The previous prime is 20019547. The next prime is 20019577. The reversal of 20019563 is 36591002.

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 20019563 - 2⁴ = 20019547 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (20019463) 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, 21845 + ... + 22742.

It is an arithmetic number, because the mean of its divisors is an integer number (5016150).

Almost surely, 2^20019563 is an apocalyptic number.

20019563 is a deficient number, since it is larger than the sum of its proper divisors (45037).

20019563 is an equidigital number, since it uses as much as digits as its factorization.

20019563 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 45036.

The product of its (nonzero) digits is 1620, while the sum is 26.

The square root of 20019563 is about 4474.3226302984. The cubic root of 20019563 is about 271.5302364050.

The spelling of 20019563 in words is "twenty million, nineteen thousand, five hundred sixty-three".