205218061 has 4 divisors (see below), whose sum is σ = 205560124. Its totient is φ = 204876000.

The previous prime is 205218049. The next prime is 205218089. The reversal of 205218061 is 160812502.

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 113422500 + 91795561 = 10650^2 + 9581^2 .

It is a cyclic number.

It is not a de Polignac number, because 205218061 - 2²⁵ = 171663629 is a prime.

It is a super-2 number, since 2×205218061² = 84228905121199442, which contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (205218011) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 170130 + ... + 171331.

It is an arithmetic number, because the mean of its divisors is an integer number (51390031).

Almost surely, 2^205218061 is an apocalyptic number.

It is an amenable number.

205218061 is a deficient number, since it is larger than the sum of its proper divisors (342063).

205218061 is an equidigital number, since it uses as much as digits as its factorization.

205218061 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 342062.

The product of its (nonzero) digits is 960, while the sum is 25.

The square root of 205218061 is about 14325.4340597414. The cubic root of 205218061 is about 589.8458478822.

It can be divided in two parts, 20521 and 8061, that added together give a palindrome (28582).

The spelling of 205218061 in words is "two hundred five million, two hundred eighteen thousand, sixty-one".