1664028 has 36 divisors (see below), whose sum is σ = 4455360. Its totient is φ = 521856.

The previous prime is 1664021. The next prime is 1664053. The reversal of 1664028 is 8204661.

1664028 is a `hidden beast` number, since 16 + 640 + 2 + 8 = 666.

It is a tau number, because it is divible by the number of its divisors (36).

It is a junction number, because it is equal to n+sod(n) for n = 1663992 and 1664010.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1664021) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 748 + ... + 1971.

It is an arithmetic number, because the mean of its divisors is an integer number (123760).

2^1664028 is an apocalyptic number.

1664028 is a gapful number since it is divisible by the number (18) formed by its first and last digit.

It is an amenable number.

1664028 is an abundant number, since it is smaller than the sum of its proper divisors (2791332).

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

1664028 is a wasteful number, since it uses less digits than its factorization.

1664028 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2746 (or 2741 counting only the distinct ones).

The product of its (nonzero) digits is 2304, while the sum is 27.

The square root of 1664028 is about 1289.9720927214. The cubic root of 1664028 is about 118.5005073951.

Adding to 1664028 its reverse (8204661), we get a palindrome (9868689).

The spelling of 1664028 in words is "one million, six hundred sixty-four thousand, twenty-eight".