20166563 has 4 divisors (see below), whose sum is σ = 20216280. Its totient is φ = 20116848.

The previous prime is 20166557. The next prime is 20166583. The reversal of 20166563 is 36566102.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 36566102 = 2 ⋅18283051.

It is a cyclic number.

It is not a de Polignac number, because 20166563 - 2⁶ = 20166499 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (20166583) 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, 24245 + ... + 25062.

It is an arithmetic number, because the mean of its divisors is an integer number (5054070).

Almost surely, 2^20166563 is an apocalyptic number.

20166563 is a deficient number, since it is larger than the sum of its proper divisors (49717).

20166563 is an equidigital number, since it uses as much as digits as its factorization.

20166563 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 49716.

The product of its (nonzero) digits is 6480, while the sum is 29.

The square root of 20166563 is about 4490.7196527951. The cubic root of 20166563 is about 272.1932153337.

The spelling of 20166563 in words is "twenty million, one hundred sixty-six thousand, five hundred sixty-three".