28161280 has 108 divisors (see below), whose sum is σ = 78642900. Its totient is φ = 9633792.

The previous prime is 28161277. The next prime is 28161313. The reversal of 28161280 is 8216182.

It can be written as a sum of positive squares in 2 ways, for example, as 13660416 + 14500864 = 3696^2 + 3808^2 .

It is a Harshad number since it is a multiple of its sum of digits (28).

It is a congruent number.

It is an unprimeable number.

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 in 11 ways as a sum of consecutive naturals, for example, 62496 + ... + 62944.

It is an arithmetic number, because the mean of its divisors is an integer number (728175).

Almost surely, 2^28161280 is an apocalyptic number.

28161280 is a gapful number since it is divisible by the number (20) 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 28161280, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (39321450).

28161280 is an abundant number, since it is smaller than the sum of its proper divisors (50481620).

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

28161280 is an equidigital number, since it uses as much as digits as its factorization.

28161280 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 484 (or 463 counting only the distinct ones).

The product of its (nonzero) digits is 1536, while the sum is 28.

The square root of 28161280 is about 5306.7202677360. The cubic root of 28161280 is about 304.2408064304.

It can be divided in two parts, 28161 and 280, that added together give a triangular number (28441 = T₂₃₈).

The spelling of 28161280 in words is "twenty-eight million, one hundred sixty-one thousand, two hundred eighty".