28998221 has 8 divisors (see below), whose sum is σ = 33190080. Its totient is φ = 24818688.

The previous prime is 28998217. The next prime is 28998227. The reversal of 28998221 is 12289982.

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 28998221 - 2² = 28998217 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (28998227) 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, 2690 + ... + 8076.

It is an arithmetic number, because the mean of its divisors is an integer number (4148760).

Almost surely, 2^28998221 is an apocalyptic number.

It is an amenable number.

28998221 is a deficient number, since it is larger than the sum of its proper divisors (4191859).

28998221 is an equidigital number, since it uses as much as digits as its factorization.

28998221 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 6163.

The product of its digits is 41472, while the sum is 41.

The square root of 28998221 is about 5384.9996285979. Note that the first 3 decimals coincide. The cubic root of 28998221 is about 307.2254000819.

The spelling of 28998221 in words is "twenty-eight million, nine hundred ninety-eight thousand, two hundred twenty-one".