206870981 has 2 divisors, whose sum is σ = 206870982. Its totient is φ = 206870980.

The previous prime is 206870971. The next prime is 206871073. The reversal of 206870981 is 189078602.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 202606756 + 4264225 = 14234^2 + 2065^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-206870981 is a prime.

It is a super-2 number, since 2×206870981² = 85591205559804722, which contains 22 as substring.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (206870921) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 103435490 + 103435491.

It is an arithmetic number, because the mean of its divisors is an integer number (103435491).

Almost surely, 2^206870981 is an apocalyptic number.

It is an amenable number.

206870981 is a deficient number, since it is larger than the sum of its proper divisors (1).

206870981 is an equidigital number, since it uses as much as digits as its factorization.

206870981 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 48384, while the sum is 41.

The square root of 206870981 is about 14383.0101508690. The cubic root of 206870981 is about 591.4252443416.

The spelling of 206870981 in words is "two hundred six million, eight hundred seventy thousand, nine hundred eighty-one".