28143680 has 56 divisors (see below), whose sum is σ = 68857368. Its totient is φ = 10948608.

The previous prime is 28143679. The next prime is 28143707. The reversal of 28143680 is 8634182.

It can be written as a sum of positive squares in 4 ways, for example, as 6390784 + 21752896 = 2528^2 + 4664^2 .

It is a Harshad number since it is a multiple of its sum of digits (32).

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 10652 + ... + 13028.

Almost surely, 2^28143680 is an apocalyptic number.

28143680 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 28143680, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (34428684).

28143680 is an abundant number, since it is smaller than the sum of its proper divisors (40713688).

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

28143680 is a wasteful number, since it uses less digits than its factorization.

28143680 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2431 (or 2421 counting only the distinct ones).

The product of its (nonzero) digits is 9216, while the sum is 32.

The square root of 28143680 is about 5305.0617338538. The cubic root of 28143680 is about 304.1774126017.

The spelling of 28143680 in words is "twenty-eight million, one hundred forty-three thousand, six hundred eighty".