206581891645 has 16 divisors (see below), whose sum is σ = 256461390720. Its totient is φ = 159557428800.

The previous prime is 206581891583. The next prime is 206581891651. The reversal of 206581891645 is 546198185602.

It is not a de Polignac number, because 206581891645 - 2⁷ = 206581891517 is a prime.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 3507490 + ... + 3565900.

It is an arithmetic number, because the mean of its divisors is an integer number (16028836920).

Almost surely, 2^206581891645 is an apocalyptic number.

It is an amenable number.

206581891645 is a deficient number, since it is larger than the sum of its proper divisors (49879499075).

206581891645 is a wasteful number, since it uses less digits than its factorization.

206581891645 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 82836.

The product of its (nonzero) digits is 4147200, while the sum is 55.

The spelling of 206581891645 in words is "two hundred six billion, five hundred eighty-one million, eight hundred ninety-one thousand, six hundred forty-five".