28102505 has 8 divisors (see below), whose sum is σ = 33755400. Its totient is φ = 22460416.

The previous prime is 28102469. The next prime is 28102519. The reversal of 28102505 is 50520182.

28102505 = 3748² + 3749².

It can be written as a sum of positive squares in 4 ways, for example, as 23104 + 28079401 = 152^2 + 5299^2 .

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 28102505 - 2⁶ = 28102441 is a prime.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 5051 + ... + 9039.

It is an arithmetic number, because the mean of its divisors is an integer number (4219425).

Almost surely, 2^28102505 is an apocalyptic number.

28102505 is the 3749-th centered square number.

It is an amenable number.

28102505 is a deficient number, since it is larger than the sum of its proper divisors (5652895).

28102505 is a wasteful number, since it uses less digits than its factorization.

28102505 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5403.

The product of its (nonzero) digits is 800, while the sum is 23.

The square root of 28102505 is about 5301.1795857149. The cubic root of 28102505 is about 304.0290001478.

Adding to 28102505 its reverse (50520182), we get a palindrome (78622687).

The spelling of 28102505 in words is "twenty-eight million, one hundred two thousand, five hundred five".