205801665243 has 16 divisors (see below), whose sum is σ = 277438815360. Its totient is φ = 135687184256.

The previous prime is 205801665239. The next prime is 205801665257. The reversal of 205801665243 is 342566108502.

It is a cyclic number.

It is not a de Polignac number, because 205801665243 - 2² = 205801665239 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 205801665195 and 205801665204.

It is not an unprimeable number, because it can be changed into a prime (205801665233) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 357678 + ... + 734531.

It is an arithmetic number, because the mean of its divisors is an integer number (17339925960).

Almost surely, 2^205801665243 is an apocalyptic number.

205801665243 is a deficient number, since it is larger than the sum of its proper divisors (71637150117).

205801665243 is a wasteful number, since it uses less digits than its factorization.

205801665243 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1092906.

The product of its (nonzero) digits is 345600, while the sum is 42.

The spelling of 205801665243 in words is "two hundred five billion, eight hundred one million, six hundred sixty-five thousand, two hundred forty-three".