28781130 has 64 divisors (see below), whose sum is σ = 80582400. Its totient is φ = 6576192.

The previous prime is 28781101. The next prime is 28781141. The reversal of 28781130 is 3118782.

It is a happy number.

It is a Harshad number since it is a multiple of its sum of digits (30).

It is an unprimeable number.

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 31 ways as a sum of consecutive naturals, for example, 8892 + ... + 11688.

It is an arithmetic number, because the mean of its divisors is an integer number (1259100).

Almost surely, 2^28781130 is an apocalyptic number.

It is a practical number, because each smaller number is the sum of distinct divisors of 28781130, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (40291200).

28781130 is an abundant number, since it is smaller than the sum of its proper divisors (51801270).

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

28781130 is a wasteful number, since it uses less digits than its factorization.

28781130 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2828 (or 2814 counting only the distinct ones).

The product of its (nonzero) digits is 2688, while the sum is 30.

The square root of 28781130 is about 5364.8047494760. The cubic root of 28781130 is about 306.4568126875.

The spelling of 28781130 in words is "twenty-eight million, seven hundred eighty-one thousand, one hundred thirty".