28220556 has 96 divisors (see below), whose sum is σ = 83066368. Its totient is φ = 7257600.

The previous prime is 28220551. The next prime is 28220579. The reversal of 28220556 is 65502282.

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 not an unprimeable number, because it can be changed into a prime (28220551) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 46656 + ... + 47256.

Almost surely, 2^28220556 is an apocalyptic number.

28220556 is a gapful number since it is divisible by the number (26) 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 28220556, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (41533184).

28220556 is an abundant number, since it is smaller than the sum of its proper divisors (54845812).

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

28220556 is a wasteful number, since it uses less digits than its factorization.

28220556 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 671 (or 669 counting only the distinct ones).

The product of its (nonzero) digits is 9600, while the sum is 30.

The square root of 28220556 is about 5312.3023257341. The cubic root of 28220556 is about 304.4541198828.

The spelling of 28220556 in words is "twenty-eight million, two hundred twenty thousand, five hundred fifty-six".