840666 has 8 divisors (see below), whose sum is σ = 1681344. Its totient is φ = 280220.

The previous prime is 840661. The next prime is 840683. The reversal of 840666 is 666048.

It is a happy number.

It is a sphenic number, since it is the product of 3 distinct primes.

840666 is an admirable number.

It is not an unprimeable number, because it can be changed into a prime (840661) by changing a digit.

840666 is an untouchable number, because it is not equal to the sum of proper divisors of any number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 70050 + ... + 70061.

It is an arithmetic number, because the mean of its divisors is an integer number (210168).

2⁸⁴⁰⁶⁶⁶ is an apocalyptic number.

840666 is a primitive abundant number, since it is smaller than the sum of its proper divisors, none of which is abundant.

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

840666 is a wasteful number, since it uses less digits than its factorization.

840666 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 140116.

The product of its (nonzero) digits is 6912, while the sum is 30.

The square root of 840666 is about 916.8783997892. The cubic root of 840666 is about 94.3788094014.

The spelling of 840666 in words is "eight hundred forty thousand, six hundred sixty-six".