28668240 has 120 divisors (see below), whose sum is σ = 99669960. Its totient is φ = 7375872.

The previous prime is 28668221. The next prime is 28668247. The reversal of 28668240 is 4286682.

28668240 = 17³ + 18³ + ... + 103³.

It can be written as a sum of positive squares in 4 ways, for example, as 11128896 + 17539344 = 3336^2 + 4188^2 .

It is a tau number, because it is divible by the number of its divisors (120).

It is a Harshad number since it is a multiple of its sum of digits (36).

It is a junction number, because it is equal to n+sod(n) for n = 28668195 and 28668204.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (28668247) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 20194 + ... + 21566.

It is an arithmetic number, because the mean of its divisors is an integer number (830583).

Almost surely, 2^28668240 is an apocalyptic number.

28668240 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 28668240, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (49834980).

28668240 is an abundant number, since it is smaller than the sum of its proper divisors (71001720).

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

28668240 is a wasteful number, since it uses less digits than its factorization.

28668240 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1421 (or 1412 counting only the distinct ones).

The product of its (nonzero) digits is 36864, while the sum is 36.

The square root of 28668240 is about 5354.2730599027. The cubic root of 28668240 is about 306.0556095269.

The spelling of 28668240 in words is "twenty-eight million, six hundred sixty-eight thousand, two hundred forty".