28260021 has 8 divisors (see below), whose sum is σ = 37705824. Its totient is φ = 18827120.

The previous prime is 28260017. The next prime is 28260041. The reversal of 28260021 is 12006282.

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 28260021 - 2² = 28260017 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 28260021.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (28260041) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 4606 + ... + 8816.

It is an arithmetic number, because the mean of its divisors is an integer number (4713228).

Almost surely, 2^28260021 is an apocalyptic number.

It is an amenable number.

28260021 is a deficient number, since it is larger than the sum of its proper divisors (9445803).

28260021 is a wasteful number, since it uses less digits than its factorization.

28260021 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 6451.

The product of its (nonzero) digits is 384, while the sum is 21.

The square root of 28260021 is about 5316.0155191647. The cubic root of 28260021 is about 304.5959749343.

The spelling of 28260021 in words is "twenty-eight million, two hundred sixty thousand, twenty-one".