128287221 has 16 divisors (see below), whose sum is σ = 181808640. Its totient is φ = 80233200.

The previous prime is 128287199. The next prime is 128287241. The reversal of 128287221 is 122782821.

It is not a de Polignac number, because 128287221 - 2⁶ = 128287157 is a prime.

It is a super-3 number, since 3×128287221³ (a number of 25 digits) contains 333 as substring. Note that it is a super-d number also for d = 2.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (128287241) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 5055 + ... + 16796.

It is an arithmetic number, because the mean of its divisors is an integer number (11363040).

Almost surely, 2^128287221 is an apocalyptic number.

It is an amenable number.

128287221 is a deficient number, since it is larger than the sum of its proper divisors (53521419).

128287221 is a wasteful number, since it uses less digits than its factorization.

128287221 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 21976.

The product of its digits is 7168, while the sum is 33.

The square root of 128287221 is about 11326.3948809849. The cubic root of 128287221 is about 504.3450922997.

The spelling of 128287221 in words is "one hundred twenty-eight million, two hundred eighty-seven thousand, two hundred twenty-one".