20643229 has 2 divisors, whose sum is σ = 20643230. Its totient is φ = 20643228.

The previous prime is 20643223. The next prime is 20643239. The reversal of 20643229 is 92234602.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 19377604 + 1265625 = 4402^2 + 1125^2 .

It is a cyclic number.

It is not a de Polignac number, because 20643229 - 2⁵ = 20643197 is a prime.

It is a super-2 number, since 2×20643229² = 852285807092882, which contains 22 as substring.

It is a junction number, because it is equal to n+sod(n) for n = 20643197 and 20643206.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (20643223) 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, 10321614 + 10321615.

It is an arithmetic number, because the mean of its divisors is an integer number (10321615).

Almost surely, 2^20643229 is an apocalyptic number.

It is an amenable number.

20643229 is a deficient number, since it is larger than the sum of its proper divisors (1).

20643229 is an equidigital number, since it uses as much as digits as its factorization.

20643229 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 5184, while the sum is 28.

The square root of 20643229 is about 4543.4820347394. The cubic root of 20643229 is about 274.3210978012.

The spelling of 20643229 in words is "twenty million, six hundred forty-three thousand, two hundred twenty-nine".