205666225 has 6 divisors (see below), whose sum is σ = 255026150. Its totient is φ = 164532960.

The previous prime is 205666217. The next prime is 205666229. The reversal of 205666225 is 522666502.

It can be written as a sum of positive squares in 3 ways, for example, as 71639296 + 134026929 = 8464^2 + 11577^2 .

It is not a de Polignac number, because 205666225 - 2³ = 205666217 is a prime.

It is a super-2 number, since 2×205666225² = 84597192211501250, which contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (205666229) 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 5 ways as a sum of consecutive naturals, for example, 4113300 + ... + 4113349.

Almost surely, 2^205666225 is an apocalyptic number.

205666225 is a gapful number since it is divisible by the number (25) formed by its first and last digit.

It is an amenable number.

205666225 is a deficient number, since it is larger than the sum of its proper divisors (49359925).

205666225 is an equidigital number, since it uses as much as digits as its factorization.

205666225 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 8226659 (or 8226654 counting only the distinct ones).

The product of its (nonzero) digits is 43200, while the sum is 34.

The square root of 205666225 is about 14341.0677775401. The cubic root of 205666225 is about 590.2749125807.

The spelling of 205666225 in words is "two hundred five million, six hundred sixty-six thousand, two hundred twenty-five".