20580209 has 4 divisors (see below), whose sum is σ = 22163316. Its totient is φ = 18997104.

The previous prime is 20580179. The next prime is 20580221. The reversal of 20580209 is 90208502.

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 13897984 + 6682225 = 3728^2 + 2585^2 .

It is a cyclic number.

It is not a de Polignac number, because 20580209 - 2²⁴ = 3802993 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (20580229) 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, 791534 + ... + 791559.

It is an arithmetic number, because the mean of its divisors is an integer number (5540829).

Almost surely, 2^20580209 is an apocalyptic number.

It is an amenable number.

20580209 is a deficient number, since it is larger than the sum of its proper divisors (1583107).

20580209 is a wasteful number, since it uses less digits than its factorization.

20580209 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1583106.

The product of its (nonzero) digits is 1440, while the sum is 26.

The square root of 20580209 is about 4536.5415241128. The cubic root of 20580209 is about 274.0416625514.

The spelling of 20580209 in words is "twenty million, five hundred eighty thousand, two hundred nine".