666442 has 16 divisors (see below), whose sum is σ = 1153152. Its totient is φ = 282960.

The previous prime is 666439. The next prime is 666461. The reversal of 666442 is 244666.

It is a nialpdrome in base 10.

It is a self number, because there is not a number n which added to its sum of digits gives 666442.

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, 2403 + ... + 2665.

It is an arithmetic number, because the mean of its divisors is an integer number (72072).

2⁶⁶⁶⁴⁴² is an apocalyptic number.

666442 is a deficient number, since it is larger than the sum of its proper divisors (486710).

666442 is a wasteful number, since it uses less digits than its factorization.

666442 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 453.

The product of its digits is 6912, while the sum is 28.

The square root of 666442 is about 816.3589896608. The cubic root of 666442 is about 87.3482321505.

The spelling of 666442 in words is "six hundred sixty-six thousand, four hundred forty-two".