20852809 has 2 divisors, whose sum is σ = 20852810. Its totient is φ = 20852808.

The previous prime is 20852803. The next prime is 20852831. The reversal of 20852809 is 90825802.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 10791225 + 10061584 = 3285^2 + 3172^2 .

It is a cyclic number.

It is not a de Polignac number, because 20852809 - 2⁹ = 20852297 is a prime.

It is a super-3 number, since 3×20852809³ (a number of 23 digits) contains 333 as substring.

It is not a weakly prime, because it can be changed into another prime (20852803) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10426404 + 10426405.

It is an arithmetic number, because the mean of its divisors is an integer number (10426405).

Almost surely, 2^20852809 is an apocalyptic number.

It is an amenable number.

20852809 is a deficient number, since it is larger than the sum of its proper divisors (1).

20852809 is an equidigital number, since it uses as much as digits as its factorization.

20852809 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 11520, while the sum is 34.

The square root of 20852809 is about 4566.4875998956. The cubic root of 20852809 is about 275.2463203493.

The spelling of 20852809 in words is "twenty million, eight hundred fifty-two thousand, eight hundred nine".