866491 has 4 divisors (see below), whose sum is σ = 896400. Its totient is φ = 836584.

The previous prime is 866477. The next prime is 866513. The reversal of 866491 is 194668.

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

It is a cyclic number.

It is not a de Polignac number, because 866491 - 2⁹ = 865979 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (866431) 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, 14911 + ... + 14968.

It is an arithmetic number, because the mean of its divisors is an integer number (224100).

2⁸⁶⁶⁴⁹¹ is an apocalyptic number.

866491 is a deficient number, since it is larger than the sum of its proper divisors (29909).

866491 is a wasteful number, since it uses less digits than its factorization.

866491 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 29908.

The product of its digits is 10368, while the sum is 34.

The square root of 866491 is about 930.8549833352. The cubic root of 866491 is about 95.3355080709.

The spelling of 866491 in words is "eight hundred sixty-six thousand, four hundred ninety-one".