28243820 has 48 divisors (see below), whose sum is σ = 65300256. Its totient is φ = 10260800.

The previous prime is 28243811. The next prime is 28243837. The reversal of 28243820 is 2834282.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 26090 + ... + 27150.

It is an arithmetic number, because the mean of its divisors is an integer number (1360422).

Almost surely, 2^28243820 is an apocalyptic number.

28243820 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 28243820, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (32650128).

28243820 is an abundant number, since it is smaller than the sum of its proper divisors (37056436).

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

28243820 is a wasteful number, since it uses less digits than its factorization.

28243820 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1103 (or 1079 counting only the distinct ones).

The product of its (nonzero) digits is 6144, while the sum is 29.

The square root of 28243820 is about 5314.4915090722. The cubic root of 28243820 is about 304.5377572057.

The spelling of 28243820 in words is "twenty-eight million, two hundred forty-three thousand, eight hundred twenty".