205442021317 has 8 divisors (see below), whose sum is σ = 221522862456. Its totient is φ = 189400838592.

The previous prime is 205442021273. The next prime is 205442021341. The reversal of 205442021317 is 713120244502.

It is a happy number.

It can be written as a sum of positive squares in 4 ways, for example, as 14373372321 + 191068648996 = 119889^2 + 437114^2 .

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 205442021317 - 2¹⁹ = 205441497029 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 (205442061317) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 9903838 + ... + 9924559.

It is an arithmetic number, because the mean of its divisors is an integer number (27690357807).

Almost surely, 2^205442021317 is an apocalyptic number.

It is an amenable number.

205442021317 is a deficient number, since it is larger than the sum of its proper divisors (16080841139).

205442021317 is a wasteful number, since it uses less digits than its factorization.

205442021317 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 19829207.

The product of its (nonzero) digits is 13440, while the sum is 31.

Adding to 205442021317 its reverse (713120244502), we get a palindrome (918562265819).

The spelling of 205442021317 in words is "two hundred five billion, four hundred forty-two million, twenty-one thousand, three hundred seventeen".