28120400 has 180 divisors, whose sum is σ = 85890336. Its totient is φ = 8659200.

The previous prime is 28120387. The next prime is 28120423. The reversal of 28120400 is 402182.

28120400 = T₄₇₅ + T₄₇₆ + ... + T₆₅₀.

It is a congruent number.

It is an unprimeable number.

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 35 ways as a sum of consecutive naturals, for example, 338759 + ... + 338841.

Almost surely, 2^28120400 is an apocalyptic number.

28120400 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 28120400, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (42945168).

28120400 is an abundant number, since it is smaller than the sum of its proper divisors (57769936).

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

28120400 is a wasteful number, since it uses less digits than its factorization.

28120400 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 130 (or 108 counting only the distinct ones).

The product of its (nonzero) digits is 128, while the sum is 17.

The square root of 28120400 is about 5302.8671490053. The cubic root of 28120400 is about 304.0935192426.

Adding to 28120400 its reverse (402182), we get a palindrome (28522582).

The spelling of 28120400 in words is "twenty-eight million, one hundred twenty thousand, four hundred".