28717920 has 432 divisors, whose sum is σ = 127724688. Its totient is φ = 5806080.

The previous prime is 28717907. The next prime is 28717921. The reversal of 28717920 is 2971782.

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

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (28717921) by changing a digit.

It is a polite number, since it can be written in 71 ways as a sum of consecutive naturals, for example, 776142 + ... + 776178.

It is an arithmetic number, because the mean of its divisors is an integer number (295659).

Almost surely, 2^28717920 is an apocalyptic number.

28717920 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 28717920, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (63862344).

28717920 is an abundant number, since it is smaller than the sum of its proper divisors (99006768).

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

28717920 is a wasteful number, since it uses less digits than its factorization.

28717920 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 83 (or 65 counting only the distinct ones).

The product of its (nonzero) digits is 14112, while the sum is 36.

The square root of 28717920 is about 5358.9103369995. The cubic root of 28717920 is about 306.2322982966.

The spelling of 28717920 in words is "twenty-eight million, seven hundred seventeen thousand, nine hundred twenty".