28321020 has 324 divisors, whose sum is σ = 113906520. Its totient is φ = 5660928.

The previous prime is 28320979. The next prime is 28321061. The reversal of 28321020 is 2012382.

It is a happy number.

It is an interprime number because it is at equal distance from previous prime (28320979) and next prime (28321061).

It is a Harshad number since it is a multiple of its sum of digits (18).

It is a junction number, because it is equal to n+sod(n) for n = 28320984 and 28321002.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 107 ways as a sum of consecutive naturals, for example, 1490571 + ... + 1490589.

Almost surely, 2^28321020 is an apocalyptic number.

28321020 is a gapful number since it is divisible by the number (20) 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 28321020, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (56953260).

28321020 is an abundant number, since it is smaller than the sum of its proper divisors (85585500).

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

28321020 is a wasteful number, since it uses less digits than its factorization.

28321020 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 74 (or 49 counting only the distinct ones).

The product of its (nonzero) digits is 192, while the sum is 18.

The square root of 28321020 is about 5321.7497122657. The cubic root of 28321020 is about 304.8149733277.

The spelling of 28321020 in words is "twenty-eight million, three hundred twenty-one thousand, twenty".