28191312 has 60 divisors (see below), whose sum is σ = 79528020. Its totient is φ = 9321984.

The previous prime is 28191301. The next prime is 28191323. The reversal of 28191312 is 21319182.

It is an interprime number because it is at equal distance from previous prime (28191301) and next prime (28191323).

It can be written as a sum of positive squares in 2 ways, for example, as 8156736 + 20034576 = 2856^2 + 4476^2 .

It is a nude number because it is divisible by every one of its digits.

It is a congruent number.

It is an unprimeable number.

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 11 ways as a sum of consecutive naturals, for example, 19014 + ... + 20442.

It is an arithmetic number, because the mean of its divisors is an integer number (1325467).

Almost surely, 2^28191312 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 28191312, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (39764010).

28191312 is an abundant number, since it is smaller than the sum of its proper divisors (51336708).

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

28191312 is a wasteful number, since it uses less digits than its factorization.

28191312 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1580 (or 1571 counting only the distinct ones).

The product of its digits is 864, while the sum is 27.

The square root of 28191312 is about 5309.5491334011. The cubic root of 28191312 is about 304.3489183942.

The spelling of 28191312 in words is "twenty-eight million, one hundred ninety-one thousand, three hundred twelve".