28055621 has 16 divisors (see below), whose sum is σ = 31449600. Its totient is φ = 24812400.

The previous prime is 28055581. The next prime is 28055623. The reversal of 28055621 is 12655082.

It is a cyclic number.

It is not a de Polignac number, because 28055621 - 2¹⁴ = 28039237 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (28055623) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 90056 + ... + 90366.

It is an arithmetic number, because the mean of its divisors is an integer number (1965600).

Almost surely, 2^28055621 is an apocalyptic number.

It is an amenable number.

28055621 is a deficient number, since it is larger than the sum of its proper divisors (3393979).

28055621 is a wasteful number, since it uses less digits than its factorization.

28055621 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 520.

The product of its (nonzero) digits is 4800, while the sum is 29.

The square root of 28055621 is about 5296.7557051463. The cubic root of 28055621 is about 303.8598333802.

The spelling of 28055621 in words is "twenty-eight million, fifty-five thousand, six hundred twenty-one".