891217 has 4 divisors (see below), whose sum is σ = 912996. Its totient is φ = 869440.

The previous prime is 891179. The next prime is 891223. The reversal of 891217 is 712198.

891217 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 46656 + 844561 = 216^2 + 919^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-891217 is a prime.

It is a Duffinian number.

It is a nialpdrome in base 16.

It is not an unprimeable number, because it can be changed into a prime (891277) 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, 10828 + ... + 10909.

It is an arithmetic number, because the mean of its divisors is an integer number (228249).

2⁸⁹¹²¹⁷ is an apocalyptic number.

It is an amenable number.

891217 is a deficient number, since it is larger than the sum of its proper divisors (21779).

891217 is a wasteful number, since it uses less digits than its factorization.

891217 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 21778.

The product of its digits is 1008, while the sum is 28.

The square root of 891217 is about 944.0429015675. The cubic root of 891217 is about 96.2338411058.

The spelling of 891217 in words is "eight hundred ninety-one thousand, two hundred seventeen".