20201309 has 8 divisors (see below), whose sum is σ = 20768760. Its totient is φ = 19646880.

The previous prime is 20201303. The next prime is 20201329. The reversal of 20201309 is 90310202.

It can be written as a sum of positive squares in 4 ways, for example, as 15578809 + 4622500 = 3947^2 + 2150^2 .

It is not a de Polignac number, because 20201309 - 2⁸ = 20201053 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20201303) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 226937 + ... + 227025.

It is an arithmetic number, because the mean of its divisors is an integer number (2596095).

Almost surely, 2^20201309 is an apocalyptic number.

It is an amenable number.

20201309 is a deficient number, since it is larger than the sum of its proper divisors (567451).

20201309 is an frugal number, since it uses more digits than its factorization.

20201309 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 272 (or 150 counting only the distinct ones).

The product of its (nonzero) digits is 108, while the sum is 17.

The square root of 20201309 is about 4494.5866328284. The cubic root of 20201309 is about 272.3494508307.

The spelling of 20201309 in words is "twenty million, two hundred one thousand, three hundred nine".