861886261 has 2 divisors, whose sum is σ = 861886262. Its totient is φ = 861886260.

The previous prime is 861886241. The next prime is 861886271. The reversal of 861886261 is 162688168.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 861422500 + 463761 = 29350^2 + 681^2 .

It is a cyclic number.

It is not a de Polignac number, because 861886261 - 2²³ = 853497653 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (861886231) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 430943130 + 430943131.

It is an arithmetic number, because the mean of its divisors is an integer number (430943131).

Almost surely, 2^861886261 is an apocalyptic number.

It is an amenable number.

861886261 is a deficient number, since it is larger than the sum of its proper divisors (1).

861886261 is an equidigital number, since it uses as much as digits as its factorization.

861886261 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 221184, while the sum is 46.

The square root of 861886261 is about 29357.8994650503. The cubic root of 861886261 is about 951.6632951905.

The spelling of 861886261 in words is "eight hundred sixty-one million, eight hundred eighty-six thousand, two hundred sixty-one".