206128639249 has 8 divisors (see below), whose sum is σ = 221990419112. Its totient is φ = 190267678080.

The previous prime is 206128639247. The next prime is 206128639271. The reversal of 206128639249 is 942936821602.

It can be written as a sum of positive squares in 4 ways, for example, as 74751387649 + 131377251600 = 273407^2 + 362460^2 .

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 206128639249 - 2¹ = 206128639247 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 206128639196 and 206128639205.

It is not an unprimeable number, because it can be changed into a prime (206128639247) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 380167 + ... + 746179.

It is an arithmetic number, because the mean of its divisors is an integer number (27748802389).

Almost surely, 2^206128639249 is an apocalyptic number.

It is an amenable number.

206128639249 is a deficient number, since it is larger than the sum of its proper divisors (15861779863).

206128639249 is a wasteful number, since it uses less digits than its factorization.

206128639249 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 409347.

The product of its (nonzero) digits is 2239488, while the sum is 52.

The spelling of 206128639249 in words is "two hundred six billion, one hundred twenty-eight million, six hundred thirty-nine thousand, two hundred forty-nine".