915891 has 4 divisors (see below), whose sum is σ = 1221192. Its totient is φ = 610592.

The previous prime is 915881. The next prime is 915911. The reversal of 915891 is 198519.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 198519 = 3 ⋅66173.

It is a cyclic number.

It is not a de Polignac number, because 915891 - 2⁷ = 915763 is a prime.

It is a D-number.

It is not an unprimeable number, because it can be changed into a prime (915851) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 152646 + ... + 152651.

It is an arithmetic number, because the mean of its divisors is an integer number (305298).

2⁹¹⁵⁸⁹¹ is an apocalyptic number.

915891 is a deficient number, since it is larger than the sum of its proper divisors (305301).

915891 is a wasteful number, since it uses less digits than its factorization.

915891 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 305300.

The product of its digits is 3240, while the sum is 33.

The square root of 915891 is about 957.0219433221. The cubic root of 915891 is about 97.1138705944.

The spelling of 915891 in words is "nine hundred fifteen thousand, eight hundred ninety-one".