20855663 has 2 divisors, whose sum is σ = 20855664. Its totient is φ = 20855662.

The previous prime is 20855657. The next prime is 20855689. The reversal of 20855663 is 36655802.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 20855663 - 2¹⁴ = 20839279 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (20855603) 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 as a sum of consecutive naturals, namely, 10427831 + 10427832.

It is an arithmetic number, because the mean of its divisors is an integer number (10427832).

Almost surely, 2^20855663 is an apocalyptic number.

20855663 is a deficient number, since it is larger than the sum of its proper divisors (1).

20855663 is an equidigital number, since it uses as much as digits as its factorization.

20855663 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 43200, while the sum is 35.

The square root of 20855663 is about 4566.8000832092. The cubic root of 20855663 is about 275.2588768856.

The spelling of 20855663 in words is "twenty million, eight hundred fifty-five thousand, six hundred sixty-three".