28021525 has 24 divisors (see below), whose sum is σ = 42050880. Its totient is φ = 18082560.

The previous prime is 28021507. The next prime is 28021529. The reversal of 28021525 is 52512082.

It is not a de Polignac number, because 28021525 - 2⁹ = 28021013 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (25).

It is a self number, because there is not a number n which added to its sum of digits gives 28021525.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (28021529) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 1735 + ... + 7684.

It is an arithmetic number, because the mean of its divisors is an integer number (1752120).

Almost surely, 2^28021525 is an apocalyptic number.

28021525 is a gapful number since it is divisible by the number (25) formed by its first and last digit.

It is an amenable number.

28021525 is a deficient number, since it is larger than the sum of its proper divisors (14029355).

28021525 is a wasteful number, since it uses less digits than its factorization.

28021525 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 9453 (or 9448 counting only the distinct ones).

The product of its (nonzero) digits is 1600, while the sum is 25.

The square root of 28021525 is about 5293.5361527055. The cubic root of 28021525 is about 303.7366898490.

The spelling of 28021525 in words is "twenty-eight million, twenty-one thousand, five hundred twenty-five".