206678216831 has 2 divisors, whose sum is σ = 206678216832. Its totient is φ = 206678216830.

The previous prime is 206678216819. The next prime is 206678216881. The reversal of 206678216831 is 138612876602.

It is an a-pointer prime, because the next prime (206678216881) can be obtained adding 206678216831 to its sum of digits (50).

It is a weak prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-206678216831 is a prime.

It is a super-2 number, since 2×206678216831² (a number of 23 digits) contains 22 as substring.

It is a self number, because there is not a number n which added to its sum of digits gives 206678216831.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (206678216881) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 103339108415 + 103339108416.

It is an arithmetic number, because the mean of its divisors is an integer number (103339108416).

Almost surely, 2^206678216831 is an apocalyptic number.

206678216831 is a deficient number, since it is larger than the sum of its proper divisors (1).

206678216831 is an equidigital number, since it uses as much as digits as its factorization.

206678216831 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 1161216, while the sum is 50.

The spelling of 206678216831 in words is "two hundred six billion, six hundred seventy-eight million, two hundred sixteen thousand, eight hundred thirty-one".