205215869 has 2 divisors, whose sum is σ = 205215870. Its totient is φ = 205215868.

The previous prime is 205215833. The next prime is 205215889. The reversal of 205215869 is 968512502.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 125328025 + 79887844 = 11195^2 + 8938^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-205215869 is a prime.

It is a super-2 number, since 2×205215869² = 84227105778850322, which contains 22 as substring.

It is a Sophie Germain prime.

It is a Curzon number.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (205215889) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 102607934 + 102607935.

It is an arithmetic number, because the mean of its divisors is an integer number (102607935).

Almost surely, 2^205215869 is an apocalyptic number.

It is an amenable number.

205215869 is a deficient number, since it is larger than the sum of its proper divisors (1).

205215869 is an equidigital number, since it uses as much as digits as its factorization.

205215869 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 43200, while the sum is 38.

The square root of 205215869 is about 14325.3575522568. The cubic root of 205215869 is about 589.8437477638.

The spelling of 205215869 in words is "two hundred five million, two hundred fifteen thousand, eight hundred sixty-nine".