206819155805 has 6 divisors (see below), whose sum is σ = 248184207258. Its totient is φ = 165454511120.

The previous prime is 206819155769. The next prime is 206819155817. The reversal of 206819155805 is 508551918602.

It is a happy number.

It can be written as a sum of positive squares in 3 ways, for example, as 11436591364 + 195382564441 = 106942^2 + 442021^2 .

It is not a de Polignac number, because 206819155805 - 2⁸ = 206819155549 is a prime.

It is a Duffinian number.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 915215 + ... + 1118595.

It is an arithmetic number, because the mean of its divisors is an integer number (41364034543).

Almost surely, 2^206819155805 is an apocalyptic number.

It is an amenable number.

206819155805 is a deficient number, since it is larger than the sum of its proper divisors (41365051453).

206819155805 is an frugal number, since it uses more digits than its factorization.

206819155805 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 406767 (or 203386 counting only the distinct ones).

The product of its (nonzero) digits is 864000, while the sum is 50.

The spelling of 206819155805 in words is "two hundred six billion, eight hundred nineteen million, one hundred fifty-five thousand, eight hundred five".