205238009 has 4 divisors (see below), whose sum is σ = 205289316. Its totient is φ = 205186704.

The previous prime is 205237997. The next prime is 205238021. The reversal of 205238009 is 900832502.

It is a semiprime because it is the product of two primes.

It is an interprime number because it is at equal distance from previous prime (205237997) and next prime (205238021).

It can be written as a sum of positive squares in 2 ways, for example, as 51552400 + 153685609 = 7180^2 + 12397^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-205238009 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (205232009) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 19094 + ... + 27839.

It is an arithmetic number, because the mean of its divisors is an integer number (51322329).

Almost surely, 2^205238009 is an apocalyptic number.

It is an amenable number.

205238009 is a deficient number, since it is larger than the sum of its proper divisors (51307).

205238009 is an equidigital number, since it uses as much as digits as its factorization.

205238009 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 51306.

The product of its (nonzero) digits is 4320, while the sum is 29.

The square root of 205238009 is about 14326.1302869966. The cubic root of 205238009 is about 589.8649590392.

The spelling of 205238009 in words is "two hundred five million, two hundred thirty-eight thousand, nine".