28538765 has 4 divisors (see below), whose sum is σ = 34246524. Its totient is φ = 22831008.

The previous prime is 28538761. The next prime is 28538771. The reversal of 28538765 is 56783582.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 56783582 = 2 ⋅28391791.

It can be written as a sum of positive squares in 2 ways, for example, as 9205156 + 19333609 = 3034^2 + 4397^2 .

It is a cyclic number.

It is not a de Polignac number, because 28538765 - 2² = 28538761 is a prime.

It is a super-2 number, since 2×28538765² = 1628922215450450, which contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (28538761) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 2853872 + ... + 2853881.

It is an arithmetic number, because the mean of its divisors is an integer number (8561631).

Almost surely, 2^28538765 is an apocalyptic number.

It is an amenable number.

28538765 is a deficient number, since it is larger than the sum of its proper divisors (5707759).

28538765 is an equidigital number, since it uses as much as digits as its factorization.

28538765 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5707758.

The product of its digits is 403200, while the sum is 44.

The square root of 28538765 is about 5342.1685671645. The cubic root of 28538765 is about 305.5941656016.

The spelling of 28538765 in words is "twenty-eight million, five hundred thirty-eight thousand, seven hundred sixty-five".