664428 has 24 divisors (see below), whose sum is σ = 1642032. Its totient is φ = 208384.

The previous prime is 664427. The next prime is 664441. The reversal of 664428 is 824466.

It is a hoax number, since the sum of its digits (30) coincides with the sum of the digits of its distinct prime factors.

It is a junction number, because it is equal to n+sod(n) for n = 664395 and 664404.

It is not an unprimeable number, because it can be changed into a prime (664421) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 1425 + ... + 1832.

It is an arithmetic number, because the mean of its divisors is an integer number (68418).

2⁶⁶⁴⁴²⁸ is an apocalyptic number.

664428 is a gapful number since it is divisible by the number (68) formed by its first and last digit.

It is an amenable number.

664428 is an abundant number, since it is smaller than the sum of its proper divisors (977604).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

664428 is a wasteful number, since it uses less digits than its factorization.

664428 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3281 (or 3279 counting only the distinct ones).

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

The square root of 664428 is about 815.1245303633. The cubic root of 664428 is about 87.2601540441.

The spelling of 664428 in words is "six hundred sixty-four thousand, four hundred twenty-eight".