28509664 has 12 divisors (see below), whose sum is σ = 56128464. Its totient is φ = 14254816.

The previous prime is 28509659. The next prime is 28509667. The reversal of 28509664 is 46690582.

It is a happy number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (28509667) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 445432 + ... + 445495.

It is an arithmetic number, because the mean of its divisors is an integer number (4677372).

Almost surely, 2^28509664 is an apocalyptic number.

It is an amenable number.

28509664 is a deficient number, since it is larger than the sum of its proper divisors (27618800).

28509664 is an equidigital number, since it uses as much as digits as its factorization.

28509664 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 890937 (or 890929 counting only the distinct ones).

The product of its (nonzero) digits is 103680, while the sum is 40.

The square root of 28509664 is about 5339.4441658285. Note that the first 3 decimals coincide. The cubic root of 28509664 is about 305.4902587426.

The spelling of 28509664 in words is "twenty-eight million, five hundred nine thousand, six hundred sixty-four".