205550661 has 8 divisors (see below), whose sum is σ = 275749600. Its totient is φ = 136192752.

The previous prime is 205550647. The next prime is 205550743. The reversal of 205550661 is 166055502.

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

It is not a de Polignac number, because 205550661 - 2¹⁰ = 205549637 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (205550641) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 209686 + ... + 210663.

It is an arithmetic number, because the mean of its divisors is an integer number (34468700).

Almost surely, 2^205550661 is an apocalyptic number.

It is an amenable number.

205550661 is a deficient number, since it is larger than the sum of its proper divisors (70198939).

205550661 is a wasteful number, since it uses less digits than its factorization.

205550661 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 420515.

The product of its (nonzero) digits is 9000, while the sum is 30.

The square root of 205550661 is about 14337.0380832304. The cubic root of 205550661 is about 590.1643332337.

The spelling of 205550661 in words is "two hundred five million, five hundred fifty thousand, six hundred sixty-one".