28721376 has 72 divisors (see below), whose sum is σ = 84337344. Its totient is φ = 9262080.

The previous prime is 28721353. The next prime is 28721383. The reversal of 28721376 is 67312782.

28721376 is a `hidden beast` number, since 287 + 2 + 1 + 376 = 666.

It is a tau number, because it is divible by the number of its divisors (72).

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

It is a self number, because there is not a number n which added to its sum of digits gives 28721376.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 7320 + ... + 10536.

It is an arithmetic number, because the mean of its divisors is an integer number (1171352).

Almost surely, 2^28721376 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 28721376, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (42168672).

28721376 is an abundant number, since it is smaller than the sum of its proper divisors (55615968).

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

28721376 is a wasteful number, since it uses less digits than its factorization.

28721376 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3264 (or 3253 counting only the distinct ones).

The product of its digits is 28224, while the sum is 36.

The square root of 28721376 is about 5359.2327809118. The cubic root of 28721376 is about 306.2445821060.

The spelling of 28721376 in words is "twenty-eight million, seven hundred twenty-one thousand, three hundred seventy-six".