20806047 has 12 divisors (see below), whose sum is σ = 30206800. Its totient is φ = 13799808.

The previous prime is 20806039. The next prime is 20806057. The reversal of 20806047 is 74060802.

It is not a de Polignac number, because 20806047 - 2³ = 20806039 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 20806047.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20806057) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 4018 + ... + 7599.

Almost surely, 2^20806047 is an apocalyptic number.

20806047 is a deficient number, since it is larger than the sum of its proper divisors (9400753).

20806047 is a wasteful number, since it uses less digits than its factorization.

20806047 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 11822 (or 11819 counting only the distinct ones).

The product of its (nonzero) digits is 2688, while the sum is 27.

The square root of 20806047 is about 4561.3645984508. The cubic root of 20806047 is about 275.0404216064.

Adding to 20806047 its reverse (74060802), we get a palindrome (94866849).

The spelling of 20806047 in words is "twenty million, eight hundred six thousand, forty-seven".