20818229 has 2 divisors, whose sum is σ = 20818230. Its totient is φ = 20818228.

The previous prime is 20818223. The next prime is 20818247. The reversal of 20818229 is 92281802.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 20566225 + 252004 = 4535^2 + 502^2 .

It is a cyclic number.

It is not a de Polignac number, because 20818229 - 2¹² = 20814133 is a prime.

It is a Chen prime.

It is equal to p_1319189 and since 20818229 and 1319189 have the same sum of digits, it is a Honaker prime.

It is a junction number, because it is equal to n+sod(n) for n = 20818195 and 20818204.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (20818223) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10409114 + 10409115.

It is an arithmetic number, because the mean of its divisors is an integer number (10409115).

Almost surely, 2^20818229 is an apocalyptic number.

It is an amenable number.

20818229 is a deficient number, since it is larger than the sum of its proper divisors (1).

20818229 is an equidigital number, since it uses as much as digits as its factorization.

20818229 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 4608, while the sum is 32.

The square root of 20818229 is about 4562.6997490521. The cubic root of 20818229 is about 275.0940901178.

The spelling of 20818229 in words is "twenty million, eight hundred eighteen thousand, two hundred twenty-nine".