205891645 has 8 divisors (see below), whose sum is σ = 247171680. Its totient is φ = 164645520.

The previous prime is 205891639. The next prime is 205891649. The reversal of 205891645 is 546198502.

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

It is not a de Polignac number, because 205891645 - 2⁵ = 205891613 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 205891598 and 205891607.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (205891649) 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 in 7 ways as a sum of consecutive naturals, for example, 7690 + ... + 21700.

It is an arithmetic number, because the mean of its divisors is an integer number (30896460).

Almost surely, 2^205891645 is an apocalyptic number.

It is an amenable number.

205891645 is a deficient number, since it is larger than the sum of its proper divisors (41280035).

205891645 is a wasteful number, since it uses less digits than its factorization.

205891645 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 16955.

The product of its (nonzero) digits is 86400, while the sum is 40.

The square root of 205891645 is about 14348.9248726168. The cubic root of 205891645 is about 590.4904903323.

The spelling of 205891645 in words is "two hundred five million, eight hundred ninety-one thousand, six hundred forty-five".