28653521 has 4 divisors (see below), whose sum is σ = 30857652. Its totient is φ = 26449392.

The previous prime is 28653511. The next prime is 28653553. The reversal of 28653521 is 12535682.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 12535682 = 2 ⋅6267841.

It can be written as a sum of positive squares in 2 ways, for example, as 2755600 + 25897921 = 1660^2 + 5089^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-28653521 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (28653511) 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, 1102046 + ... + 1102071.

It is an arithmetic number, because the mean of its divisors is an integer number (7714413).

Almost surely, 2^28653521 is an apocalyptic number.

It is an amenable number.

28653521 is a deficient number, since it is larger than the sum of its proper divisors (2204131).

28653521 is a wasteful number, since it uses less digits than its factorization.

28653521 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2204130.

The product of its digits is 14400, while the sum is 32.

The square root of 28653521 is about 5352.8983737785. The cubic root of 28653521 is about 306.0032216614.

The spelling of 28653521 in words is "twenty-eight million, six hundred fifty-three thousand, five hundred twenty-one".