28820340 has 144 divisors (see below), whose sum is σ = 96196800. Its totient is φ = 7143552.

The previous prime is 28820291. The next prime is 28820347. The reversal of 28820340 is 4302882.

It is a super-2 number, since 2×28820340² = 1661223995431200, which contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (27).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (28820347) 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, 543754 + ... + 543806.

Almost surely, 2^28820340 is an apocalyptic number.

28820340 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 28820340, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (48098400).

28820340 is an abundant number, since it is smaller than the sum of its proper divisors (67376460).

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

28820340 is a wasteful number, since it uses less digits than its factorization.

28820340 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 143 (or 82 counting only the distinct ones).

The product of its (nonzero) digits is 3072, while the sum is 27.

The square root of 28820340 is about 5368.4578791307. The cubic root of 28820340 is about 306.5959167811.

The spelling of 28820340 in words is "twenty-eight million, eight hundred twenty thousand, three hundred forty".