20820889 has 2 divisors, whose sum is σ = 20820890. Its totient is φ = 20820888.

The previous prime is 20820887. The next prime is 20820929. The reversal of 20820889 is 98802802.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 15681600 + 5139289 = 3960^2 + 2267^2 .

It is a cyclic number.

It is not a de Polignac number, because 20820889 - 2¹ = 20820887 is a prime.

Together with 20820887, it forms a pair of twin primes.

It is not a weakly prime, because it can be changed into another prime (20820881) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10410444 + 10410445.

It is an arithmetic number, because the mean of its divisors is an integer number (10410445).

Almost surely, 2^20820889 is an apocalyptic number.

It is an amenable number.

20820889 is a deficient number, since it is larger than the sum of its proper divisors (1).

20820889 is an equidigital number, since it uses as much as digits as its factorization.

20820889 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 18432, while the sum is 37.

The square root of 20820889 is about 4562.9912338290. The cubic root of 20820889 is about 275.1058061179.

The spelling of 20820889 in words is "twenty million, eight hundred twenty thousand, eight hundred eighty-nine".