28720525 has 12 divisors (see below), whose sum is σ = 36372672. Its totient is φ = 22486640.

The previous prime is 28720513. The next prime is 28720553. The reversal of 28720525 is 52502782.

It is not a de Polignac number, because 28720525 - 2²³ = 20331917 is a prime.

It is a Duffinian number.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 11047 + ... + 13396.

It is an arithmetic number, because the mean of its divisors is an integer number (3031056).

Almost surely, 2^28720525 is an apocalyptic number.

28720525 is a gapful number since it is divisible by the number (25) formed by its first and last digit.

It is an amenable number.

28720525 is a deficient number, since it is larger than the sum of its proper divisors (7652147).

28720525 is a wasteful number, since it uses less digits than its factorization.

28720525 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 24500 (or 24495 counting only the distinct ones).

The product of its (nonzero) digits is 11200, while the sum is 31.

The square root of 28720525 is about 5359.1533846308. The cubic root of 28720525 is about 306.2415574516.

The spelling of 28720525 in words is "twenty-eight million, seven hundred twenty thousand, five hundred twenty-five".