28720559 has 4 divisors (see below), whose sum is σ = 32823504. Its totient is φ = 24617616.

The previous prime is 28720553. The next prime is 28720577. The reversal of 28720559 is 95502782.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 95502782 = 2 ⋅47751391.

It is a cyclic number.

It is not a de Polignac number, because 28720559 - 2⁸ = 28720303 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (28720553) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 2051462 + ... + 2051475.

It is an arithmetic number, because the mean of its divisors is an integer number (8205876).

Almost surely, 2^28720559 is an apocalyptic number.

28720559 is a deficient number, since it is larger than the sum of its proper divisors (4102945).

28720559 is an equidigital number, since it uses as much as digits as its factorization.

28720559 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4102944.

The product of its (nonzero) digits is 50400, while the sum is 38.

The square root of 28720559 is about 5359.1565567727. The cubic root of 28720559 is about 306.2416782967.

The spelling of 28720559 in words is "twenty-eight million, seven hundred twenty thousand, five hundred fifty-nine".