28655921 has 8 divisors (see below), whose sum is σ = 32922624. Its totient is φ = 24432480.

The previous prime is 28655903. The next prime is 28655929. The reversal of 28655921 is 12955682.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 28655921 - 2¹⁰ = 28654897 is a prime.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (28655929) 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 7 ways as a sum of consecutive naturals, for example, 9380 + ... + 12053.

It is an arithmetic number, because the mean of its divisors is an integer number (4115328).

Almost surely, 2^28655921 is an apocalyptic number.

It is an amenable number.

28655921 is a deficient number, since it is larger than the sum of its proper divisors (4266703).

28655921 is a wasteful number, since it uses less digits than its factorization.

28655921 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 21631.

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

The square root of 28655921 is about 5353.1225467011. The cubic root of 28655921 is about 306.0117649655.

The spelling of 28655921 in words is "twenty-eight million, six hundred fifty-five thousand, nine hundred twenty-one".