20136209 has 4 divisors (see below), whose sum is σ = 20159040. Its totient is φ = 20113380.

The previous prime is 20136197. The next prime is 20136217. The reversal of 20136209 is 90263102.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4, and also an emirpimes, since its reverse is a distinct semiprime: 90263102 = 2 ⋅45131551.

It is a cyclic number.

It is not a de Polignac number, because 20136209 - 2²⁰ = 19087633 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (20136709) 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, 10037 + ... + 11874.

It is an arithmetic number, because the mean of its divisors is an integer number (5039760).

Almost surely, 2^20136209 is an apocalyptic number.

It is an amenable number.

20136209 is a deficient number, since it is larger than the sum of its proper divisors (22831).

20136209 is an equidigital number, since it uses as much as digits as its factorization.

20136209 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 22830.

The product of its (nonzero) digits is 648, while the sum is 23.

The square root of 20136209 is about 4487.3387436208. The cubic root of 20136209 is about 272.0565815465.

The spelling of 20136209 in words is "twenty million, one hundred thirty-six thousand, two hundred nine".