28987780 has 12 divisors (see below), whose sum is σ = 60874380. Its totient is φ = 11595104.

The previous prime is 28987769. The next prime is 28987781. The reversal of 28987780 is 8778982.

It can be written as a sum of positive squares in 2 ways, for example, as 10342656 + 18645124 = 3216^2 + 4318^2 .

It is not an unprimeable number, because it can be changed into a prime (28987781) 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 3 ways as a sum of consecutive naturals, for example, 724675 + ... + 724714.

It is an arithmetic number, because the mean of its divisors is an integer number (5072865).

Almost surely, 2^28987780 is an apocalyptic number.

28987780 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

28987780 is an abundant number, since it is smaller than the sum of its proper divisors (31886600).

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

28987780 is a wasteful number, since it uses less digits than its factorization.

28987780 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1449398 (or 1449396 counting only the distinct ones).

The product of its (nonzero) digits is 451584, while the sum is 49.

The square root of 28987780 is about 5384.0300890690. The cubic root of 28987780 is about 307.1885228143.

The spelling of 28987780 in words is "twenty-eight million, nine hundred eighty-seven thousand, seven hundred eighty".