20806285 has 4 divisors (see below), whose sum is σ = 24967548. Its totient is φ = 16645024.

The previous prime is 20806277. The next prime is 20806339. The reversal of 20806285 is 58260802.

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

It can be written as a sum of positive squares in 2 ways, for example, as 12752041 + 8054244 = 3571^2 + 2838^2 .

It is a cyclic number.

It is not a de Polignac number, because 20806285 - 2³ = 20806277 is a prime.

It is a Smith number, since the sum of its digits (31) coincides with the sum of the digits of its prime factors. Since it is squarefree, it is also a hoax number.

It is a Duffinian number.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 2080624 + ... + 2080633.

It is an arithmetic number, because the mean of its divisors is an integer number (6241887).

Almost surely, 2^20806285 is an apocalyptic number.

It is an amenable number.

20806285 is a deficient number, since it is larger than the sum of its proper divisors (4161263).

20806285 is an equidigital number, since it uses as much as digits as its factorization.

20806285 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4161262.

The product of its (nonzero) digits is 7680, while the sum is 31.

The square root of 20806285 is about 4561.3906870603. The cubic root of 20806285 is about 275.0414703299.

The spelling of 20806285 in words is "twenty million, eight hundred six thousand, two hundred eighty-five".