20809158 has 16 divisors (see below), whose sum is σ = 43428096. Its totient is φ = 6634760.

The previous prime is 20809157. The next prime is 20809163. The reversal of 20809158 is 85190802.

It is a happy number.

It is a Smith number, since the sum of its digits (33) coincides with the sum of the digits of its prime factors. Since it is squarefree, it is also a hoax number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20809157) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 75258 + ... + 75533.

It is an arithmetic number, because the mean of its divisors is an integer number (2714256).

Almost surely, 2^20809158 is an apocalyptic number.

20809158 is an abundant number, since it is smaller than the sum of its proper divisors (22618938).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

20809158 is a wasteful number, since it uses less digits than its factorization.

20809158 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 150819.

The product of its (nonzero) digits is 5760, while the sum is 33.

The square root of 20809158 is about 4561.7056020747. The cubic root of 20809158 is about 275.0541292897.

The spelling of 20809158 in words is "twenty million, eight hundred nine thousand, one hundred fifty-eight".