666842 has 16 divisors (see below), whose sum is σ = 1156032. Its totient is φ = 285120.

The previous prime is 666829. The next prime is 666857. The reversal of 666842 is 248666.

It is a happy number.

666842 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a junction number, because it is equal to n+sod(n) for n = 666799 and 666808.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 518 + ... + 1265.

It is an arithmetic number, because the mean of its divisors is an integer number (72252).

2⁶⁶⁶⁸⁴² is an apocalyptic number.

666842 is a deficient number, since it is larger than the sum of its proper divisors (489190).

666842 is a wasteful number, since it uses less digits than its factorization.

666842 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1813.

The product of its digits is 13824, while the sum is 32.

The square root of 666842 is about 816.6039431695. The cubic root of 666842 is about 87.3657041911.

The spelling of 666842 in words is "six hundred sixty-six thousand, eight hundred forty-two".