205117139 has 4 divisors (see below), whose sum is σ = 205330224. Its totient is φ = 204904056.

The previous prime is 205117127. The next prime is 205117193. The reversal of 205117139 is 931711502.

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

It is a cyclic number.

It is not a de Polignac number, because 205117139 - 2¹² = 205113043 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (205117639) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 105092 + ... + 107025.

It is an arithmetic number, because the mean of its divisors is an integer number (51332556).

Almost surely, 2^205117139 is an apocalyptic number.

205117139 is a deficient number, since it is larger than the sum of its proper divisors (213085).

205117139 is an equidigital number, since it uses as much as digits as its factorization.

205117139 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 213084.

The product of its (nonzero) digits is 1890, while the sum is 29.

The square root of 205117139 is about 14321.9111504017. The cubic root of 205117139 is about 589.7491406962.

The spelling of 205117139 in words is "two hundred five million, one hundred seventeen thousand, one hundred thirty-nine".