664842 has 8 divisors (see below), whose sum is σ = 1329696. Its totient is φ = 221612.

The previous prime is 664799. The next prime is 664843. The reversal of 664842 is 248466.

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

664842 is an admirable number.

It is not an unprimeable number, because it can be changed into a prime (664843) by changing a digit.

664842 is an untouchable number, because it is not equal to the sum of proper divisors of any number.

It is a pernicious number, because its binary representation contains a prime number (7) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 55398 + ... + 55409.

It is an arithmetic number, because the mean of its divisors is an integer number (166212).

2⁶⁶⁴⁸⁴² is an apocalyptic number.

664842 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.

664842 is a wasteful number, since it uses less digits than its factorization.

664842 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 110812.

The product of its digits is 9216, while the sum is 30.

The square root of 664842 is about 815.3784397444. The cubic root of 664842 is about 87.2782739925.

The spelling of 664842 in words is "six hundred sixty-four thousand, eight hundred forty-two".