128221287 has 8 divisors (see below), whose sum is σ = 171848304. Its totient is φ = 85037568.

The previous prime is 128221283. The next prime is 128221307. The reversal of 128221287 is 782122821.

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 128221287 - 2² = 128221283 is a prime.

It is a Smith number, since the sum of its digits (33) coincides with the sum of the digits of its prime factors. Since it is squarefree, it is also a hoax number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (128221283) 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, 110148 + ... + 111305.

It is an arithmetic number, because the mean of its divisors is an integer number (21481038).

Almost surely, 2^128221287 is an apocalyptic number.

128221287 is a deficient number, since it is larger than the sum of its proper divisors (43627017).

128221287 is a wasteful number, since it uses less digits than its factorization.

128221287 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 221649.

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

The square root of 128221287 is about 11323.4838720245. The cubic root of 128221287 is about 504.2586737470.

The spelling of 128221287 in words is "one hundred twenty-eight million, two hundred twenty-one thousand, two hundred eighty-seven".