28220478 has 64 divisors (see below), whose sum is σ = 68511744. Its totient is φ = 7632000.

The previous prime is 28220473. The next prime is 28220497. The reversal of 28220478 is 87402282.

It is a Harshad number since it is a multiple of its sum of digits (33).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (28220473) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 26068 + ... + 27128.

It is an arithmetic number, because the mean of its divisors is an integer number (1070496).

Almost surely, 2^28220478 is an apocalyptic number.

It is a practical number, because each smaller number is the sum of distinct divisors of 28220478, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (34255872).

28220478 is an abundant number, since it is smaller than the sum of its proper divisors (40291266).

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

28220478 is a wasteful number, since it uses less digits than its factorization.

28220478 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1121.

The product of its (nonzero) digits is 14336, while the sum is 33.

The square root of 28220478 is about 5312.2949842794. The cubic root of 28220478 is about 304.4538393846.

It can be divided in two parts, 282204 and 78, that added together give a palindrome (282282).

The spelling of 28220478 in words is "twenty-eight million, two hundred twenty thousand, four hundred seventy-eight".