28044721 has 8 divisors (see below), whose sum is σ = 28339200. Its totient is φ = 27752160.

The previous prime is 28044707. The next prime is 28044727. The reversal of 28044721 is 12744082.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 28044721 - 2¹³ = 28036529 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 28044721.

It is not an unprimeable number, because it can be changed into a prime (28044727) 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, 68365 + ... + 68773.

It is an arithmetic number, because the mean of its divisors is an integer number (3542400).

Almost surely, 2^28044721 is an apocalyptic number.

It is an amenable number.

28044721 is a deficient number, since it is larger than the sum of its proper divisors (294479).

28044721 is a wasteful number, since it uses less digits than its factorization.

28044721 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 959.

The product of its (nonzero) digits is 3584, while the sum is 28.

The square root of 28044721 is about 5295.7266734604. The cubic root of 28044721 is about 303.8204770220.

The spelling of 28044721 in words is "twenty-eight million, forty-four thousand, seven hundred twenty-one".