115915861 has 2 divisors, whose sum is σ = 115915862. Its totient is φ = 115915860.

The previous prime is 115915859. The next prime is 115915889. The reversal of 115915861 is 168519511.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 60933636 + 54982225 = 7806^2 + 7415^2 .

It is an emirp because it is prime and its reverse (168519511) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 115915861 - 2¹ = 115915859 is a prime.

Together with 115915859, it forms a pair of twin primes.

It is a self number, because there is not a number n which added to its sum of digits gives 115915861.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (115915801) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 57957930 + 57957931.

It is an arithmetic number, because the mean of its divisors is an integer number (57957931).

Almost surely, 2^115915861 is an apocalyptic number.

It is an amenable number.

115915861 is a deficient number, since it is larger than the sum of its proper divisors (1).

115915861 is an equidigital number, since it uses as much as digits as its factorization.

115915861 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 10800, while the sum is 37.

The square root of 115915861 is about 10766.4228506965. The cubic root of 115915861 is about 487.5819521221.

It can be divided in two parts, 1159 and 15861, that added together give a triangular number (17020 = T₁₈₄).

The spelling of 115915861 in words is "one hundred fifteen million, nine hundred fifteen thousand, eight hundred sixty-one".