128221015 has 16 divisors (see below), whose sum is σ = 167350176. Its totient is φ = 93744000.

The previous prime is 128221007. The next prime is 128221019. The reversal of 128221015 is 510122821.

It is not a de Polignac number, because 128221015 - 2³ = 128221007 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 (128221019) 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, 3201 + ... + 16330.

It is an arithmetic number, because the mean of its divisors is an integer number (10459386).

Almost surely, 2^128221015 is an apocalyptic number.

128221015 is a deficient number, since it is larger than the sum of its proper divisors (39129161).

128221015 is a wasteful number, since it uses less digits than its factorization.

128221015 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 19650.

The product of its (nonzero) digits is 320, while the sum is 22.

The square root of 128221015 is about 11323.4718615803. The cubic root of 128221015 is about 504.2583171800.

Adding to 128221015 its reverse (510122821), we get a palindrome (638343836).

The spelling of 128221015 in words is "one hundred twenty-eight million, two hundred twenty-one thousand, fifteen".