28072561 has 8 divisors (see below), whose sum is σ = 30829248. Its totient is φ = 25350000.

The previous prime is 28072549. The next prime is 28072567. The reversal of 28072561 is 16527082.

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 28072561 - 2⁷ = 28072433 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (28072567) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 6790 + ... + 10111.

It is an arithmetic number, because the mean of its divisors is an integer number (3853656).

Almost surely, 2^28072561 is an apocalyptic number.

It is an amenable number.

28072561 is a deficient number, since it is larger than the sum of its proper divisors (2756687).

28072561 is a wasteful number, since it uses less digits than its factorization.

28072561 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 17063.

The product of its (nonzero) digits is 6720, while the sum is 31.

The square root of 28072561 is about 5298.3545558975. The cubic root of 28072561 is about 303.9209779891.

The spelling of 28072561 in words is "twenty-eight million, seventy-two thousand, five hundred sixty-one".