28000000 has 126 divisors (see below), whose sum is σ = 79842728. Its totient is φ = 9600000.

The previous prime is 27999943. The next prime is 28000019. The reversal of 28000000 is 82.

It is a happy number.

It is a Harshad number since it is a multiple of its sum of digits (10).

It is a super Niven number, because it is divisible the sum of any subset of its (nonzero) digits.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 13 ways as a sum of consecutive naturals, for example, 3999997 + ... + 4000003.

Almost surely, 2^28000000 is an apocalyptic number.

28000000 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 28000000, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (39921364).

28000000 is an abundant number, since it is smaller than the sum of its proper divisors (51842728).

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

28000000 is an frugal number, since it uses more digits than its factorization.

28000000 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 53 (or 14 counting only the distinct ones).

The product of its (nonzero) digits is 16, while the sum is 10.

The square root of 28000000 is about 5291.5026221292. The cubic root of 28000000 is about 303.6588971876.

Adding to 28000000 its reverse (82), we get a palindrome (28000082).

It can be divided in two parts, 2 and 8000000, that multiplied together give a square (16000000 = 4000²).

The spelling of 28000000 in words is "twenty-eight million", and thus it is an aban number and an uban number.