28681780 has 12 divisors (see below), whose sum is σ = 60231780. Its totient is φ = 11472704.

The previous prime is 28681753. The next prime is 28681781. The reversal of 28681780 is 8718682.

It can be written as a sum of positive squares in 2 ways, for example, as 20593444 + 8088336 = 4538^2 + 2844^2 .

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (28681781) 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, 717025 + ... + 717064.

It is an arithmetic number, because the mean of its divisors is an integer number (5019315).

Almost surely, 2^28681780 is an apocalyptic number.

28681780 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

28681780 is an abundant number, since it is smaller than the sum of its proper divisors (31550000).

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

28681780 is a wasteful number, since it uses less digits than its factorization.

28681780 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1434098 (or 1434096 counting only the distinct ones).

The product of its (nonzero) digits is 43008, while the sum is 40.

The square root of 28681780 is about 5355.5373213152. The cubic root of 28681780 is about 306.1037852633.

The spelling of 28681780 in words is "twenty-eight million, six hundred eighty-one thousand, seven hundred eighty".