20798909 has 4 divisors (see below), whose sum is σ = 20836416. Its totient is φ = 20761404.

The previous prime is 20798881. The next prime is 20798927. The reversal of 20798909 is 90989702.

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.

It is a cyclic number.

It is not a de Polignac number, because 20798909 - 2⁸ = 20798653 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is a self number, because there is not a number n which added to its sum of digits gives 20798909.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20798959) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 17909 + ... + 19034.

It is an arithmetic number, because the mean of its divisors is an integer number (5209104).

Almost surely, 2^20798909 is an apocalyptic number.

It is an amenable number.

20798909 is a deficient number, since it is larger than the sum of its proper divisors (37507).

20798909 is an equidigital number, since it uses as much as digits as its factorization.

20798909 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 37506.

The product of its (nonzero) digits is 81648, while the sum is 44.

The square root of 20798909 is about 4560.5820900407. The cubic root of 20798909 is about 275.0089649970.

The spelling of 20798909 in words is "twenty million, seven hundred ninety-eight thousand, nine hundred nine".