28212840 has 128 divisors (see below), whose sum is σ = 95212800. Its totient is φ = 7430400.

The previous prime is 28212791. The next prime is 28212857. The reversal of 28212840 is 4821282.

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

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 162994 + ... + 163166.

It is an arithmetic number, because the mean of its divisors is an integer number (743850).

Almost surely, 2^28212840 is an apocalyptic number.

28212840 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 28212840, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (47606400).

28212840 is an abundant number, since it is smaller than the sum of its proper divisors (66999960).

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

28212840 is a wasteful number, since it uses less digits than its factorization.

28212840 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 344 (or 334 counting only the distinct ones).

The product of its (nonzero) digits is 2048, while the sum is 27.

The square root of 28212840 is about 5311.5760372982. The cubic root of 28212840 is about 304.4263696367.

The spelling of 28212840 in words is "twenty-eight million, two hundred twelve thousand, eight hundred forty".