28725615 has 12 divisors (see below), whose sum is σ = 49791144. Its totient is φ = 15320304.

The previous prime is 28725611. The next prime is 28725691. The reversal of 28725615 is 51652782.

It is a happy number.

28725615 is a `hidden beast` number, since 28 + 72 + 561 + 5 = 666.

It is not a de Polignac number, because 28725615 - 2² = 28725611 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 28725615.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (28725611) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 319129 + ... + 319218.

It is an arithmetic number, because the mean of its divisors is an integer number (4149262).

Almost surely, 2^28725615 is an apocalyptic number.

28725615 is a deficient number, since it is larger than the sum of its proper divisors (21065529).

28725615 is a wasteful number, since it uses less digits than its factorization.

28725615 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 638358 (or 638355 counting only the distinct ones).

The product of its digits is 33600, while the sum is 36.

The square root of 28725615 is about 5359.6282520339. The cubic root of 28725615 is about 306.2596476205.

The spelling of 28725615 in words is "twenty-eight million, seven hundred twenty-five thousand, six hundred fifteen".