28780040 has 32 divisors (see below), whose sum is σ = 64926360. Its totient is φ = 11481600.

The previous prime is 28780039. The next prime is 28780049. The reversal of 28780040 is 4008782.

It can be written as a sum of positive squares in 4 ways, for example, as 19695844 + 9084196 = 4438^2 + 3014^2 .

It is a junction number, because it is equal to n+sod(n) for n = 28779985 and 28780012.

It is not an unprimeable number, because it can be changed into a prime (28780049) by changing a digit.

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 7 ways as a sum of consecutive naturals, for example, 20150 + ... + 21530.

Almost surely, 2^28780040 is an apocalyptic number.

28780040 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

28780040 is an abundant number, since it is smaller than the sum of its proper divisors (36146320).

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

28780040 is a wasteful number, since it uses less digits than its factorization.

28780040 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1913 (or 1909 counting only the distinct ones).

The product of its (nonzero) digits is 3584, while the sum is 29.

The square root of 28780040 is about 5364.7031604740. The cubic root of 28780040 is about 306.4529439242.

The spelling of 28780040 in words is "twenty-eight million, seven hundred eighty thousand, forty".