28721936 has 40 divisors (see below), whose sum is σ = 57615360. Its totient is φ = 13862016.

The previous prime is 28721933. The next prime is 28721971. The reversal of 28721936 is 63912782.

It is a self number, because there is not a number n which added to its sum of digits gives 28721936.

It is not an unprimeable number, because it can be changed into a prime (28721933) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 74801 + ... + 75183.

It is an arithmetic number, because the mean of its divisors is an integer number (1440384).

Almost surely, 2^28721936 is an apocalyptic number.

It is an amenable number.

28721936 is an abundant number, since it is smaller than the sum of its proper divisors (28893424).

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

28721936 is a wasteful number, since it uses less digits than its factorization.

28721936 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 543 (or 537 counting only the distinct ones).

The product of its digits is 36288, while the sum is 38.

The square root of 28721936 is about 5359.2850269416. The cubic root of 28721936 is about 306.2465724453.

The spelling of 28721936 in words is "twenty-eight million, seven hundred twenty-one thousand, nine hundred thirty-six".