205240109 has 8 divisors (see below), whose sum is σ = 225435840. Its totient is φ = 185983776.

The previous prime is 205240093. The next prime is 205240121. The reversal of 205240109 is 901042502.

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 205240109 - 2⁴ = 205240093 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (23).

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (205240709) by changing a digit.

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 7 ways as a sum of consecutive naturals, for example, 234392 + ... + 235265.

It is an arithmetic number, because the mean of its divisors is an integer number (28179480).

Almost surely, 2^205240109 is an apocalyptic number.

It is an amenable number.

205240109 is a deficient number, since it is larger than the sum of its proper divisors (20195731).

205240109 is a wasteful number, since it uses less digits than its factorization.

205240109 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 469699.

The product of its (nonzero) digits is 720, while the sum is 23.

The square root of 205240109 is about 14326.2035794554. The cubic root of 205240109 is about 589.8669708696.

The spelling of 205240109 in words is "two hundred five million, two hundred forty thousand, one hundred nine".