205161193609 has 4 divisors (see below), whose sum is σ = 205200404116. Its totient is φ = 205121983104.

The previous prime is 205161193603. The next prime is 205161193637. The reversal of 205161193609 is 906391161502.

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

It can be written as a sum of positive squares in 2 ways, for example, as 108502383609 + 96658810000 = 329397^2 + 310900^2 .

It is a cyclic number.

It is not a de Polignac number, because 205161193609 - 2⁷ = 205161193481 is a prime.

It is a super-2 number, since 2×205161193609² (a number of 23 digits) contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (205161193603) 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, 19597404 + ... + 19607869.

It is an arithmetic number, because the mean of its divisors is an integer number (51300101029).

Almost surely, 2^205161193609 is an apocalyptic number.

It is an amenable number.

205161193609 is a deficient number, since it is larger than the sum of its proper divisors (39210507).

205161193609 is an equidigital number, since it uses as much as digits as its factorization.

205161193609 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 39210506.

The product of its (nonzero) digits is 87480, while the sum is 43.

The spelling of 205161193609 in words is "two hundred five billion, one hundred sixty-one million, one hundred ninety-three thousand, six hundred nine".