28207513 has 4 divisors (see below), whose sum is σ = 28218420. Its totient is φ = 28196608.

The previous prime is 28207511. The next prime is 28207541. The reversal of 28207513 is 31570282.

It is a semiprime because it is the product of two primes, and also a brilliant number, because the two primes have the same length, and also an emirpimes, since its reverse is a distinct semiprime: 31570282 = 2 ⋅15785141.

It can be written as a sum of positive squares in 2 ways, for example, as 24334489 + 3873024 = 4933^2 + 1968^2 .

It is a cyclic number.

It is not a de Polignac number, because 28207513 - 2¹ = 28207511 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (28207511) 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, 873 + ... + 7561.

It is an arithmetic number, because the mean of its divisors is an integer number (7054605).

Almost surely, 2^28207513 is an apocalyptic number.

It is an amenable number.

28207513 is a deficient number, since it is larger than the sum of its proper divisors (10907).

28207513 is an equidigital number, since it uses as much as digits as its factorization.

28207513 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 10906.

The product of its (nonzero) digits is 3360, while the sum is 28.

The square root of 28207513 is about 5311.0745617059. The cubic root of 28207513 is about 304.4072083689.

Adding to 28207513 its reverse (31570282), we get a palindrome (59777795).

The spelling of 28207513 in words is "twenty-eight million, two hundred seven thousand, five hundred thirteen".