261420205 has 4 divisors (see below), whose sum is σ = 313704252. Its totient is φ = 209136160.

The previous prime is 261420199. The next prime is 261420233. The reversal of 261420205 is 502024162.

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 204432804 + 56987401 = 14298^2 + 7549^2 .

It is not a de Polignac number, because 261420205 - 2²⁷ = 127202477 is a prime.

It is a Duffinian number.

It is a congruent number.

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, 26142016 + ... + 26142025.

It is an arithmetic number, because the mean of its divisors is an integer number (78426063).

Almost surely, 2^261420205 is an apocalyptic number.

It is an amenable number.

261420205 is a deficient number, since it is larger than the sum of its proper divisors (52284047).

261420205 is an equidigital number, since it uses as much as digits as its factorization.

261420205 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 52284046.

The product of its (nonzero) digits is 960, while the sum is 22.

The square root of 261420205 is about 16168.4942094185. The cubic root of 261420205 is about 639.4104311763.

Adding to 261420205 its reverse (502024162), we get a palindrome (763444367).

The spelling of 261420205 in words is "two hundred sixty-one million, four hundred twenty thousand, two hundred five".