864859661 has 2 divisors, whose sum is σ = 864859662. Its totient is φ = 864859660.

The previous prime is 864859657. The next prime is 864859673. The reversal of 864859661 is 166958468.

864859661 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 660798436 + 204061225 = 25706^2 + 14285^2 .

It is a cyclic number.

It is not a de Polignac number, because 864859661 - 2² = 864859657 is a prime.

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 (864859691) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 432429830 + 432429831.

It is an arithmetic number, because the mean of its divisors is an integer number (432429831).

Almost surely, 2^864859661 is an apocalyptic number.

It is an amenable number.

864859661 is a deficient number, since it is larger than the sum of its proper divisors (1).

864859661 is an equidigital number, since it uses as much as digits as its factorization.

864859661 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 2488320, while the sum is 53.

The square root of 864859661 is about 29408.4964083511. The cubic root of 864859661 is about 952.7564123000.

The spelling of 864859661 in words is "eight hundred sixty-four million, eight hundred fifty-nine thousand, six hundred sixty-one".