864761861 has 2 divisors, whose sum is σ = 864761862. Its totient is φ = 864761860.

The previous prime is 864761827. The next prime is 864761893. The reversal of 864761861 is 168167468.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 861129025 + 3632836 = 29345^2 + 1906^2 .

It is a cyclic number.

It is not a de Polignac number, because 864761861 - 2¹⁰ = 864760837 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 (864961861) 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 as a sum of consecutive naturals, namely, 432380930 + 432380931.

It is an arithmetic number, because the mean of its divisors is an integer number (432380931).

Almost surely, 2^864761861 is an apocalyptic number.

It is an amenable number.

864761861 is a deficient number, since it is larger than the sum of its proper divisors (1).

864761861 is an equidigital number, since it uses as much as digits as its factorization.

864761861 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 387072, while the sum is 47.

The square root of 864761861 is about 29406.8335765686. The cubic root of 864761861 is about 952.7204977681.

The spelling of 864761861 in words is "eight hundred sixty-four million, seven hundred sixty-one thousand, eight hundred sixty-one".