28220664 has 64 divisors (see below), whose sum is σ = 73866240. Its totient is φ = 8974080.

The previous prime is 28220659. The next prime is 28220671. The reversal of 28220664 is 46602282.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 61524 + ... + 61980.

It is an arithmetic number, because the mean of its divisors is an integer number (1154160).

Almost surely, 2^28220664 is an apocalyptic number.

28220664 is a gapful number since it is divisible by the number (24) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 28220664, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (36933120).

28220664 is an abundant number, since it is smaller than the sum of its proper divisors (45645576).

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

28220664 is a wasteful number, since it uses less digits than its factorization.

28220664 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 580 (or 576 counting only the distinct ones).

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

The square root of 28220664 is about 5312.3124908085. The cubic root of 28220664 is about 304.4545082640.

The spelling of 28220664 in words is "twenty-eight million, two hundred twenty thousand, six hundred sixty-four".