915881 has 2 divisors, whose sum is σ = 915882. Its totient is φ = 915880.

The previous prime is 915869. The next prime is 915911. The reversal of 915881 is 188519.

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., 512656 + 403225 = 716^2 + 635^2 .

It is an emirp because it is prime and its reverse (188519) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 915881 - 2¹⁰ = 914857 is a prime.

It is a super-2 number, since 2×915881² = 1677676012322, which contains 22 as substring.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (915851) 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, 457940 + 457941.

It is an arithmetic number, because the mean of its divisors is an integer number (457941).

2⁹¹⁵⁸⁸¹ is an apocalyptic number.

It is an amenable number.

915881 is a deficient number, since it is larger than the sum of its proper divisors (1).

915881 is an equidigital number, since it uses as much as digits as its factorization.

915881 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 2880, while the sum is 32.

The square root of 915881 is about 957.0167187672. The cubic root of 915881 is about 97.1135171527.

Subtracting from 915881 its sum of digits (32), we obtain a square (915849 = 957²).

The spelling of 915881 in words is "nine hundred fifteen thousand, eight hundred eighty-one".