205131405 has 32 divisors (see below), whose sum is σ = 337696128. Its totient is φ = 106265600.

The previous prime is 205131361. The next prime is 205131427. The reversal of 205131405 is 504131502.

It is not a de Polignac number, because 205131405 - 2⁶ = 205131341 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 (13) of ones.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 172222 + ... + 173408.

It is an arithmetic number, because the mean of its divisors is an integer number (10553004).

Almost surely, 2^205131405 is an apocalyptic number.

It is an amenable number.

205131405 is a deficient number, since it is larger than the sum of its proper divisors (132564723).

205131405 is a wasteful number, since it uses less digits than its factorization.

205131405 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1517.

The product of its (nonzero) digits is 600, while the sum is 21.

The square root of 205131405 is about 14322.4091897976. The cubic root of 205131405 is about 589.7628128288.

Adding to 205131405 its reverse (504131502), we get a palindrome (709262907).

The spelling of 205131405 in words is "two hundred five million, one hundred thirty-one thousand, four hundred five".