664078 has 4 divisors (see below), whose sum is σ = 996120. Its totient is φ = 332038.

The previous prime is 664067. The next prime is 664091. The reversal of 664078 is 870466.

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

It is a congruent number.

It is an unprimeable number.

664078 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 as a sum of consecutive naturals, namely, 166018 + ... + 166021.

It is an arithmetic number, because the mean of its divisors is an integer number (249030).

2⁶⁶⁴⁰⁷⁸ is an apocalyptic number.

664078 is a deficient number, since it is larger than the sum of its proper divisors (332042).

664078 is a wasteful number, since it uses less digits than its factorization.

664078 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 332041.

The product of its (nonzero) digits is 8064, while the sum is 31.

The square root of 664078 is about 814.9098109607. The cubic root of 664078 is about 87.2448293748.

The spelling of 664078 in words is "six hundred sixty-four thousand, seventy-eight".