28071021 has 8 divisors (see below), whose sum is σ = 40830624. Its totient is φ = 17012720.

The previous prime is 28071013. The next prime is 28071059. The reversal of 28071021 is 12017082.

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 28071021 - 2³ = 28071013 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (28071011) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 425286 + ... + 425351.

It is an arithmetic number, because the mean of its divisors is an integer number (5103828).

Almost surely, 2^28071021 is an apocalyptic number.

It is an amenable number.

28071021 is a deficient number, since it is larger than the sum of its proper divisors (12759603).

28071021 is a wasteful number, since it uses less digits than its factorization.

28071021 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 850651.

The product of its (nonzero) digits is 224, while the sum is 21.

The square root of 28071021 is about 5298.2092257668. The cubic root of 28071021 is about 303.9154204049.

It can be divided in two parts, 2807 and 1021, that added together give a triangular number (3828 = T₈₇).

The spelling of 28071021 in words is "twenty-eight million, seventy-one thousand, twenty-one".