861874487161 has 2 divisors, whose sum is σ = 861874487162. Its totient is φ = 861874487160.

The previous prime is 861874487153. The next prime is 861874487207. The reversal of 861874487161 is 161784478168.

It is a happy number.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 840419561536 + 21454925625 = 916744^2 + 146475^2 .

It is a cyclic number.

It is not a de Polignac number, because 861874487161 - 2³ = 861874487153 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 861874487161.

It is not a weakly prime, because it can be changed into another prime (861874487861) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 430937243580 + 430937243581.

It is an arithmetic number, because the mean of its divisors is an integer number (430937243581).

Almost surely, 2^861874487161 is an apocalyptic number.

It is an amenable number.

861874487161 is a deficient number, since it is larger than the sum of its proper divisors (1).

861874487161 is an equidigital number, since it uses as much as digits as its factorization.

861874487161 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 14450688, while the sum is 61.

The spelling of 861874487161 in words is "eight hundred sixty-one billion, eight hundred seventy-four million, four hundred eighty-seven thousand, one hundred sixty-one".