28021871 has 8 divisors (see below), whose sum is σ = 28458144. Its totient is φ = 27588960.

The previous prime is 28021841. The next prime is 28021883. The reversal of 28021871 is 17812082.

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 28021871 - 2¹⁰ = 28020847 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (28021841) 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, 19601 + ... + 20981.

It is an arithmetic number, because the mean of its divisors is an integer number (3557268).

Almost surely, 2^28021871 is an apocalyptic number.

28021871 is a deficient number, since it is larger than the sum of its proper divisors (436273).

28021871 is a wasteful number, since it uses less digits than its factorization.

28021871 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1681.

The product of its (nonzero) digits is 1792, while the sum is 29.

The square root of 28021871 is about 5293.5688339720. The cubic root of 28021871 is about 303.7379399887.

The spelling of 28021871 in words is "twenty-eight million, twenty-one thousand, eight hundred seventy-one".