28621840 has 120 divisors (see below), whose sum is σ = 75564360. Its totient is φ = 10063872.

The previous prime is 28621837. The next prime is 28621841. The reversal of 28621840 is 4812682.

It can be written as a sum of positive squares in 12 ways, for example, as 14961424 + 13660416 = 3868^2 + 3696^2 .

It is not an unprimeable number, because it can be changed into a prime (28621841) by changing a digit.

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 23 ways as a sum of consecutive naturals, for example, 392044 + ... + 392116.

It is an arithmetic number, because the mean of its divisors is an integer number (629703).

Almost surely, 2^28621840 is an apocalyptic number.

28621840 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 28621840, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (37782180).

28621840 is an abundant number, since it is smaller than the sum of its proper divisors (46942520).

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

28621840 is a wasteful number, since it uses less digits than its factorization.

28621840 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 141 (or 122 counting only the distinct ones).

The product of its (nonzero) digits is 6144, while the sum is 31.

The square root of 28621840 is about 5349.9383174014. The cubic root of 28621840 is about 305.8904017490.

The spelling of 28621840 in words is "twenty-eight million, six hundred twenty-one thousand, eight hundred forty".