20856223 has 2 divisors, whose sum is σ = 20856224. Its totient is φ = 20856222.

The previous prime is 20856221. The next prime is 20856259. The reversal of 20856223 is 32265802.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 20856223 - 2¹ = 20856221 is a prime.

Together with 20856221, it forms a pair of twin primes.

It is a junction number, because it is equal to n+sod(n) for n = 20856191 and 20856200.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (20856221) 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, 10428111 + 10428112.

It is an arithmetic number, because the mean of its divisors is an integer number (10428112).

Almost surely, 2^20856223 is an apocalyptic number.

20856223 is a deficient number, since it is larger than the sum of its proper divisors (1).

20856223 is an equidigital number, since it uses as much as digits as its factorization.

20856223 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 5760, while the sum is 28.

The square root of 20856223 is about 4566.8613948750. The cubic root of 20856223 is about 275.2613405425.

The spelling of 20856223 in words is "twenty million, eight hundred fifty-six thousand, two hundred twenty-three".