28721016 has 24 divisors (see below), whose sum is σ = 77786280. Its totient is φ = 9573648.

The previous prime is 28720987. The next prime is 28721029. The reversal of 28721016 is 61012782.

It is a tau number, because it is divible by the number of its divisors (24).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 199380 + ... + 199523.

It is an arithmetic number, because the mean of its divisors is an integer number (3241095).

Almost surely, 2^28721016 is an apocalyptic number.

It is an amenable number.

28721016 is an abundant number, since it is smaller than the sum of its proper divisors (49065264).

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

28721016 is a wasteful number, since it uses less digits than its factorization.

28721016 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 398915 (or 398908 counting only the distinct ones).

The product of its (nonzero) digits is 1344, while the sum is 27.

The square root of 28721016 is about 5359.1991939095. The cubic root of 28721016 is about 306.2433025885.

Adding to 28721016 its reverse (61012782), we get a palindrome (89733798).

The spelling of 28721016 in words is "twenty-eight million, seven hundred twenty-one thousand, sixteen".