28779220 has 12 divisors (see below), whose sum is σ = 60436404. Its totient is φ = 11511680.

The previous prime is 28779217. The next prime is 28779227. The reversal of 28779220 is 2297782.

It can be written as a sum of positive squares in 2 ways, for example, as 10784656 + 17994564 = 3284^2 + 4242^2 .

It is a self number, because there is not a number n which added to its sum of digits gives 28779220.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (28779227) 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 3 ways as a sum of consecutive naturals, for example, 719461 + ... + 719500.

It is an arithmetic number, because the mean of its divisors is an integer number (5036367).

Almost surely, 2^28779220 is an apocalyptic number.

28779220 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

28779220 is an abundant number, since it is smaller than the sum of its proper divisors (31657184).

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

28779220 is a wasteful number, since it uses less digits than its factorization.

28779220 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1438970 (or 1438968 counting only the distinct ones).

The product of its (nonzero) digits is 28224, while the sum is 37.

The square root of 28779220 is about 5364.6267344523. The cubic root of 28779220 is about 306.4500334140.

It can be divided in two parts, 287 and 79220, that added together give a cube (79507 = 43³).

The spelling of 28779220 in words is "twenty-eight million, seven hundred seventy-nine thousand, two hundred twenty".