20549309 has 8 divisors (see below), whose sum is σ = 22604160. Its totient is φ = 18679980.

The previous prime is 20549303. The next prime is 20549339. The reversal of 20549309 is 90394502.

It is a de Polignac number, because none of the positive numbers 2^k-20549309 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 (20549303) 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, 6389 + ... + 9050.

It is an arithmetic number, because the mean of its divisors is an integer number (2825520).

Almost surely, 2^20549309 is an apocalyptic number.

It is an amenable number.

20549309 is a deficient number, since it is larger than the sum of its proper divisors (2054851).

20549309 is an equidigital number, since it uses as much as digits as its factorization.

20549309 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 15472 (or 15450 counting only the distinct ones).

The product of its (nonzero) digits is 9720, while the sum is 32.

The square root of 20549309 is about 4533.1345667209. The cubic root of 20549309 is about 273.9044412542.

The spelling of 20549309 in words is "twenty million, five hundred forty-nine thousand, three hundred nine".