28921143 has 8 divisors (see below), whose sum is σ = 40238208. Its totient is φ = 18442424.

The previous prime is 28921141. The next prime is 28921147. The reversal of 28921143 is 34112982.

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 28921143 - 2¹ = 28921141 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 28921143.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (28921141) 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, 209505 + ... + 209642.

It is an arithmetic number, because the mean of its divisors is an integer number (5029776).

Almost surely, 2^28921143 is an apocalyptic number.

28921143 is a gapful number since it is divisible by the number (23) formed by its first and last digit.

28921143 is a deficient number, since it is larger than the sum of its proper divisors (11317065).

28921143 is a wasteful number, since it uses less digits than its factorization.

28921143 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 419173.

The product of its digits is 3456, while the sum is 30.

The square root of 28921143 is about 5377.8381344180. The cubic root of 28921143 is about 306.9529542724.

The spelling of 28921143 in words is "twenty-eight million, nine hundred twenty-one thousand, one hundred forty-three".