115781381 has 2 divisors, whose sum is σ = 115781382. Its totient is φ = 115781380.

The previous prime is 115781363. The next prime is 115781387. The reversal of 115781381 is 183187511.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 72760900 + 43020481 = 8530^2 + 6559^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-115781381 is a prime.

It is a super-2 number, since 2×115781381² = 26810656372534322, which contains 22 as substring.

It is equal to p_6614774 and since 115781381 and 6614774 have the same sum of digits, it is a Honaker prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (115781387) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 57890690 + 57890691.

It is an arithmetic number, because the mean of its divisors is an integer number (57890691).

Almost surely, 2^115781381 is an apocalyptic number.

It is an amenable number.

115781381 is a deficient number, since it is larger than the sum of its proper divisors (1).

115781381 is an equidigital number, since it uses as much as digits as its factorization.

115781381 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 6720, while the sum is 35.

The square root of 115781381 is about 10760.1756955916. The cubic root of 115781381 is about 487.3933227900.

The spelling of 115781381 in words is "one hundred fifteen million, seven hundred eighty-one thousand, three hundred eighty-one".