20825909 has 12 divisors (see below), whose sum is σ = 23012388. Its totient is φ = 18735360.

The previous prime is 20825891. The next prime is 20825921. The reversal of 20825909 is 90952802.

It can be written as a sum of positive squares in 6 ways, for example, as 10745284 + 10080625 = 3278^2 + 3175^2 .

It is a de Polignac number, because none of the positive numbers 2^k-20825909 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20825939) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 21377 + ... + 22329.

It is an arithmetic number, because the mean of its divisors is an integer number (1917699).

Almost surely, 2^20825909 is an apocalyptic number.

It is an amenable number.

20825909 is a deficient number, since it is larger than the sum of its proper divisors (2186479).

20825909 is an equidigital number, since it uses as much as digits as its factorization.

20825909 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1048 (or 1007 counting only the distinct ones).

The product of its (nonzero) digits is 12960, while the sum is 35.

The square root of 20825909 is about 4563.5412784372. The cubic root of 20825909 is about 275.1279140463.

The spelling of 20825909 in words is "twenty million, eight hundred twenty-five thousand, nine hundred nine".