206340821 has 2 divisors, whose sum is σ = 206340822. Its totient is φ = 206340820.

The previous prime is 206340803. The next prime is 206340847. The reversal of 206340821 is 128043602.

It is an a-pointer prime, because the next prime (206340847) can be obtained adding 206340821 to its sum of digits (26).

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 173976100 + 32364721 = 13190^2 + 5689^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-206340821 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (206340881) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 103170410 + 103170411.

It is an arithmetic number, because the mean of its divisors is an integer number (103170411).

Almost surely, 2^206340821 is an apocalyptic number.

It is an amenable number.

206340821 is a deficient number, since it is larger than the sum of its proper divisors (1).

206340821 is an equidigital number, since it uses as much as digits as its factorization.

206340821 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 2304, while the sum is 26.

The square root of 206340821 is about 14364.5682496899. The cubic root of 206340821 is about 590.9195857924.

The spelling of 206340821 in words is "two hundred six million, three hundred forty thousand, eight hundred twenty-one".