28783188 has 150 divisors (see below), whose sum is σ = 90152986. Its totient is φ = 8001504.

The previous prime is 28783141. The next prime is 28783199. The reversal of 28783188 is 88138782.

It is a happy number.

It can be written as a sum of positive squares in only one way, i.e., 28005264 + 777924 = 5292^2 + 882^2 .

It is a super-2 number, since 2×28783188² = 1656943822886688, which contains 22 as substring.

It is a congruent number.

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 49 ways as a sum of consecutive naturals, for example, 777906 + ... + 777942.

Almost surely, 2^28783188 is an apocalyptic number.

28783188 is a gapful number since it is divisible by the number (28) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 28783188, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (45076493).

28783188 is an abundant number, since it is smaller than the sum of its proper divisors (61369798).

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

28783188 is an equidigital number, since it uses as much as digits as its factorization.

28783188 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 81 (or 49 counting only the distinct ones).

The product of its digits is 172032, while the sum is 45.

The square root of 28783188 is about 5364.9965517230. The cubic root of 28783188 is about 306.4641169304.

The spelling of 28783188 in words is "twenty-eight million, seven hundred eighty-three thousand, one hundred eighty-eight".