865576661 has 2 divisors, whose sum is σ = 865576662. Its totient is φ = 865576660.

The previous prime is 865576583. The next prime is 865576681. The reversal of 865576661 is 166675568.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 836308561 + 29268100 = 28919^2 + 5410^2 .

It is a cyclic number.

It is not a de Polignac number, because 865576661 - 2¹⁰ = 865575637 is a prime.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (865576681) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 432788330 + 432788331.

It is an arithmetic number, because the mean of its divisors is an integer number (432788331).

Almost surely, 2^865576661 is an apocalyptic number.

It is an amenable number.

865576661 is a deficient number, since it is larger than the sum of its proper divisors (1).

865576661 is an equidigital number, since it uses as much as digits as its factorization.

865576661 is an evil number, because the sum of its binary digits is even.

The product of its digits is 1814400, while the sum is 50.

The square root of 865576661 is about 29420.6842374544. The cubic root of 865576661 is about 953.0196294386.

The spelling of 865576661 in words is "eight hundred sixty-five million, five hundred seventy-six thousand, six hundred sixty-one".