28956521 has 4 divisors (see below), whose sum is σ = 31588944. Its totient is φ = 26324100.

The previous prime is 28956509. The next prime is 28956527. The reversal of 28956521 is 12565982.

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 de Polignac number, because none of the positive numbers 2^k-28956521 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (28956527) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1316195 + ... + 1316216.

It is an arithmetic number, because the mean of its divisors is an integer number (7897236).

Almost surely, 2^28956521 is an apocalyptic number.

It is an amenable number.

28956521 is a deficient number, since it is larger than the sum of its proper divisors (2632423).

28956521 is a wasteful number, since it uses less digits than its factorization.

28956521 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2632422.

The product of its digits is 43200, while the sum is 38.

The square root of 28956521 is about 5381.1263690792. The cubic root of 28956521 is about 307.0780640889.

The spelling of 28956521 in words is "twenty-eight million, nine hundred fifty-six thousand, five hundred twenty-one".