28221805 has 8 divisors (see below), whose sum is σ = 35338752. Its totient is φ = 21595728.

The previous prime is 28221797. The next prime is 28221827. The reversal of 28221805 is 50812282.

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 28221805 - 2³ = 28221797 is a prime.

It is a Duffinian number.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 122589 + ... + 122818.

It is an arithmetic number, because the mean of its divisors is an integer number (4417344).

Almost surely, 2^28221805 is an apocalyptic number.

It is an amenable number.

28221805 is a deficient number, since it is larger than the sum of its proper divisors (7116947).

28221805 is a wasteful number, since it uses less digits than its factorization.

28221805 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 245435.

The product of its (nonzero) digits is 2560, while the sum is 28.

The square root of 28221805 is about 5312.4198817488. The cubic root of 28221805 is about 304.4586113793.

The spelling of 28221805 in words is "twenty-eight million, two hundred twenty-one thousand, eight hundred five".