664628 has 6 divisors (see below), whose sum is σ = 1163106. Its totient is φ = 332312.

The previous prime is 664621. The next prime is 664633. The reversal of 664628 is 826466.

It is a happy number.

It can be written as a sum of positive squares in only one way, i.e., 595984 + 68644 = 772^2 + 262^2 .

It is a junction number, because it is equal to n+sod(n) for n = 664594 and 664603.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (664621) by changing a digit.

664628 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, 83075 + ... + 83082.

It is an arithmetic number, because the mean of its divisors is an integer number (193851).

2⁶⁶⁴⁶²⁸ is an apocalyptic number.

It is an amenable number.

664628 is a deficient number, since it is larger than the sum of its proper divisors (498478).

664628 is a wasteful number, since it uses less digits than its factorization.

664628 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 166161 (or 166159 counting only the distinct ones).

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

The square root of 664628 is about 815.2472017738. The cubic root of 664628 is about 87.2689085819.

The spelling of 664628 in words is "six hundred sixty-four thousand, six hundred twenty-eight".