28307725 has 6 divisors (see below), whose sum is σ = 35101610. Its totient is φ = 22646160.

The previous prime is 28307723. The next prime is 28307759. The reversal of 28307725 is 52770382.

It can be written as a sum of positive squares in 3 ways, for example, as 5669161 + 22638564 = 2381^2 + 4758^2 .

It is not a de Polignac number, because 28307725 - 2¹ = 28307723 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (28307723) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 566130 + ... + 566179.

Almost surely, 2^28307725 is an apocalyptic number.

28307725 is a gapful number since it is divisible by the number (25) formed by its first and last digit.

It is an amenable number.

28307725 is a deficient number, since it is larger than the sum of its proper divisors (6793885).

28307725 is a wasteful number, since it uses less digits than its factorization.

28307725 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1132319 (or 1132314 counting only the distinct ones).

The product of its (nonzero) digits is 23520, while the sum is 34.

The square root of 28307725 is about 5320.5004463866. The cubic root of 28307725 is about 304.7672684855.

It can be divided in two parts, 2830772 and 5, that multiplied together give a triangular number (14153860 = T₅₃₂₀).

The spelling of 28307725 in words is "twenty-eight million, three hundred seven thousand, seven hundred twenty-five".