28067521 has 4 divisors (see below), whose sum is σ = 29287872. Its totient is φ = 26847172.

The previous prime is 28067513. The next prime is 28067531. The reversal of 28067521 is 12576082.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 28067521 - 2³ = 28067513 is a prime.

It is a super-3 number, since 3×28067521³ (a number of 23 digits) contains 333 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (28067531) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 610141 + ... + 610186.

It is an arithmetic number, because the mean of its divisors is an integer number (7321968).

Almost surely, 2^28067521 is an apocalyptic number.

It is an amenable number.

28067521 is a deficient number, since it is larger than the sum of its proper divisors (1220351).

28067521 is a wasteful number, since it uses less digits than its factorization.

28067521 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1220350.

The product of its (nonzero) digits is 6720, while the sum is 31.

The square root of 28067521 is about 5297.8789151886. The cubic root of 28067521 is about 303.9027887757.

The spelling of 28067521 in words is "twenty-eight million, sixty-seven thousand, five hundred twenty-one".