28505711 has 4 divisors (see below), whose sum is σ = 30698472. Its totient is φ = 26312952.

The previous prime is 28505699. The next prime is 28505723. The reversal of 28505711 is 11750582.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 11750582 = 2 ⋅5875291.

It is an interprime number because it is at equal distance from previous prime (28505699) and next prime (28505723).

It is a cyclic number.

It is not a de Polignac number, because 28505711 - 2¹⁰ = 28504687 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (28505011) 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, 1096361 + ... + 1096386.

It is an arithmetic number, because the mean of its divisors is an integer number (7674618).

Almost surely, 2^28505711 is an apocalyptic number.

28505711 is a deficient number, since it is larger than the sum of its proper divisors (2192761).

28505711 is a wasteful number, since it uses less digits than its factorization.

28505711 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2192760.

The product of its (nonzero) digits is 2800, while the sum is 29.

The square root of 28505711 is about 5339.0739833795. The cubic root of 28505711 is about 305.4761388660.

The spelling of 28505711 in words is "twenty-eight million, five hundred five thousand, seven hundred eleven".