28780105 has 16 divisors (see below), whose sum is σ = 35426304. Its totient is φ = 22438080.

The previous prime is 28780067. The next prime is 28780109. The reversal of 28780105 is 50108782.

It is not a de Polignac number, because 28780105 - 2¹³ = 28771913 is a prime.

It is a super-2 number, since 2×28780105² = 1656588887622050, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (28780109) 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 15 ways as a sum of consecutive naturals, for example, 38364 + ... + 39106.

It is an arithmetic number, because the mean of its divisors is an integer number (2214144).

Almost surely, 2^28780105 is an apocalyptic number.

It is an amenable number.

28780105 is a deficient number, since it is larger than the sum of its proper divisors (6646199).

28780105 is a wasteful number, since it uses less digits than its factorization.

28780105 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 936.

The product of its (nonzero) digits is 4480, while the sum is 31.

The square root of 28780105 is about 5364.7092185877. The cubic root of 28780105 is about 306.4531746330.

Adding to 28780105 its reverse (50108782), we get a palindrome (78888887).

The spelling of 28780105 in words is "twenty-eight million, seven hundred eighty thousand, one hundred five".