205861139 has 4 divisors (see below), whose sum is σ = 224575800. Its totient is φ = 187146480.

The previous prime is 205861093. The next prime is 205861157. The reversal of 205861139 is 931168502.

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

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-205861139 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 205861099 and 205861108.

It is not an unprimeable number, because it can be changed into a prime (205821139) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 9357314 + ... + 9357335.

It is an arithmetic number, because the mean of its divisors is an integer number (56143950).

Almost surely, 2^205861139 is an apocalyptic number.

205861139 is a deficient number, since it is larger than the sum of its proper divisors (18714661).

205861139 is a wasteful number, since it uses less digits than its factorization.

205861139 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 18714660.

The product of its (nonzero) digits is 12960, while the sum is 35.

The square root of 205861139 is about 14347.8618267671. The cubic root of 205861139 is about 590.4613254891.

The spelling of 205861139 in words is "two hundred five million, eight hundred sixty-one thousand, one hundred thirty-nine".