205638371242 has 8 divisors (see below), whose sum is σ = 308460154500. Its totient is φ = 102818319744.

The previous prime is 205638371219. The next prime is 205638371291. The reversal of 205638371242 is 242173836502.

It can be written as a sum of positive squares in 2 ways, for example, as 181662635961 + 23975735281 = 426219^2 + 154841^2 .

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

It is a super-2 number, since 2×205638371242² (a number of 23 digits) contains 22 as substring.

It is an unprimeable number.

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 3 ways as a sum of consecutive naturals, for example, 77817 + ... + 646012.

Almost surely, 2^205638371242 is an apocalyptic number.

205638371242 is a deficient number, since it is larger than the sum of its proper divisors (102821783258).

205638371242 is a wasteful number, since it uses less digits than its factorization.

205638371242 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 865880.

The product of its (nonzero) digits is 483840, while the sum is 43.

The spelling of 205638371242 in words is "two hundred five billion, six hundred thirty-eight million, three hundred seventy-one thousand, two hundred forty-two".