206340021 has 16 divisors (see below), whose sum is σ = 309561600. Its totient is φ = 135817344.

The previous prime is 206340007. The next prime is 206340031. The reversal of 206340021 is 120043602.

It is a happy number.

It is not a de Polignac number, because 206340021 - 2¹⁰ = 206338997 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 206339976 and 206340003.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (206340031) 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 in 15 ways as a sum of consecutive naturals, for example, 46236 + ... + 50501.

It is an arithmetic number, because the mean of its divisors is an integer number (19347600).

Almost surely, 2^206340021 is an apocalyptic number.

It is an amenable number.

206340021 is a deficient number, since it is larger than the sum of its proper divisors (103221579).

206340021 is an equidigital number, since it uses as much as digits as its factorization.

206340021 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 96825 (or 96819 counting only the distinct ones).

The product of its (nonzero) digits is 288, while the sum is 18.

The square root of 206340021 is about 14364.5404033683. The cubic root of 206340021 is about 590.9188221105.

Adding to 206340021 its reverse (120043602), we get a palindrome (326383623).

The spelling of 206340021 in words is "two hundred six million, three hundred forty thousand, twenty-one".