28409400 has 96 divisors (see below), whose sum is σ = 97873200. Its totient is φ = 7574400.

The previous prime is 28409371. The next prime is 28409411. The reversal of 28409400 is 490482.

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 23 ways as a sum of consecutive naturals, for example, 2770 + ... + 8030.

Almost surely, 2^28409400 is an apocalyptic number.

28409400 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 28409400, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (48936600).

28409400 is an abundant number, since it is smaller than the sum of its proper divisors (69463800).

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

28409400 is a wasteful number, since it uses less digits than its factorization.

28409400 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5286 (or 5271 counting only the distinct ones).

The product of its (nonzero) digits is 2304, while the sum is 27.

The square root of 28409400 is about 5330.0469041088. The cubic root of 28409400 is about 305.1317177206.

Adding to 28409400 its reverse (490482), we get a palindrome (28899882).

The spelling of 28409400 in words is "twenty-eight million, four hundred nine thousand, four hundred".