20855656189 has 2 divisors, whose sum is σ = 20855656190. Its totient is φ = 20855656188.

The previous prime is 20855656169. The next prime is 20855656267. The reversal of 20855656189 is 98165655802.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 19212732100 + 1642924089 = 138610^2 + 40533^2 .

It is a cyclic number.

It is not a de Polignac number, because 20855656189 - 2³¹ = 18708172541 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (20855656169) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10427828094 + 10427828095.

It is an arithmetic number, because the mean of its divisors is an integer number (10427828095).

Almost surely, 2^20855656189 is an apocalyptic number.

It is an amenable number.

20855656189 is a deficient number, since it is larger than the sum of its proper divisors (1).

20855656189 is an equidigital number, since it uses as much as digits as its factorization.

20855656189 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 5184000, while the sum is 55.

The spelling of 20855656189 in words is "twenty billion, eight hundred fifty-five million, six hundred fifty-six thousand, one hundred eighty-nine".