28321830 has 96 divisors (see below), whose sum is σ = 79151904. Its totient is φ = 7001088.

The previous prime is 28321819. The next prime is 28321831. The reversal of 28321830 is 3812382.

It is a Curzon number.

It is a junction number, because it is equal to n+sod(n) for n = 28321794 and 28321803.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (28321831) by changing a digit.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 163624 + ... + 163796.

It is an arithmetic number, because the mean of its divisors is an integer number (824499).

It is a vampire number, since it can be written as 3210 ⋅ 8823 (with its own digits).

Almost surely, 2^28321830 is an apocalyptic number.

It is a practical number, because each smaller number is the sum of distinct divisors of 28321830, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (39575952).

28321830 is an abundant number, since it is smaller than the sum of its proper divisors (50830074).

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

28321830 is a wasteful number, since it uses less digits than its factorization.

28321830 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 310 (or 307 counting only the distinct ones).

The product of its (nonzero) digits is 2304, while the sum is 27.

The square root of 28321830 is about 5321.8258145114. The cubic root of 28321830 is about 304.8178792703.

The spelling of 28321830 in words is "twenty-eight million, three hundred twenty-one thousand, eight hundred thirty".