28709720 has 96 divisors (see below), whose sum is σ = 72731520. Its totient is φ = 10183680.

The previous prime is 28709699. The next prime is 28709761. The reversal of 28709720 is 2790782.

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, 209492 + ... + 209628.

It is an arithmetic number, because the mean of its divisors is an integer number (757620).

Almost surely, 2^28709720 is an apocalyptic number.

28709720 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 28709720, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (36365760).

28709720 is an abundant number, since it is smaller than the sum of its proper divisors (44021800).

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

28709720 is a wasteful number, since it uses less digits than its factorization.

28709720 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 205 (or 188 counting only the distinct ones).

The product of its (nonzero) digits is 14112, while the sum is 35.

The square root of 28709720 is about 5358.1452014666. The cubic root of 28709720 is about 306.2031487401.

The spelling of 28709720 in words is "twenty-eight million, seven hundred nine thousand, seven hundred twenty".