20303209 has 4 divisors (see below), whose sum is σ = 20364880. Its totient is φ = 20241540.

The previous prime is 20303203. The next prime is 20303249. The reversal of 20303209 is 90230302.

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: 90230302 = 2 ⋅45115151.

It is a cyclic number.

It is not a de Polignac number, because 20303209 - 2¹⁷ = 20172137 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (20303203) 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, 30339 + ... + 31000.

It is an arithmetic number, because the mean of its divisors is an integer number (5091220).

Almost surely, 2^20303209 is an apocalyptic number.

It is an amenable number.

20303209 is a deficient number, since it is larger than the sum of its proper divisors (61671).

20303209 is an equidigital number, since it uses as much as digits as its factorization.

20303209 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 61670.

The product of its (nonzero) digits is 324, while the sum is 19.

The square root of 20303209 is about 4505.9082325320. The cubic root of 20303209 is about 272.8066138824.

The spelling of 20303209 in words is "twenty million, three hundred three thousand, two hundred nine".