20982563 has 4 divisors (see below), whose sum is σ = 23980080. Its totient is φ = 17985048.

The previous prime is 20982553. The next prime is 20982569. The reversal of 20982563 is 36528902.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 36528902 = 2 ⋅18264451.

It is a cyclic number.

It is not a de Polignac number, because 20982563 - 2⁶ = 20982499 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (20982569) 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, 1498748 + ... + 1498761.

It is an arithmetic number, because the mean of its divisors is an integer number (5995020).

Almost surely, 2^20982563 is an apocalyptic number.

20982563 is a deficient number, since it is larger than the sum of its proper divisors (2997517).

20982563 is an equidigital number, since it uses as much as digits as its factorization.

20982563 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2997516.

The product of its (nonzero) digits is 25920, while the sum is 35.

The square root of 20982563 is about 4580.6727671817. The cubic root of 20982563 is about 275.8160356031.

The spelling of 20982563 in words is "twenty million, nine hundred eighty-two thousand, five hundred sixty-three".