128221812 has 24 divisors (see below), whose sum is σ = 332427200. Its totient is φ = 42740568.

The previous prime is 128221783. The next prime is 128221843. The reversal of 128221812 is 218122821.

It is a Harshad number since it is a multiple of its sum of digits (27).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 593512 + ... + 593727.

Almost surely, 2^128221812 is an apocalyptic number.

128221812 is a gapful number since it is divisible by the number (12) formed by its first and last digit.

It is an amenable number.

128221812 is an abundant number, since it is smaller than the sum of its proper divisors (204205388).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

128221812 is a wasteful number, since it uses less digits than its factorization.

128221812 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1187252 (or 1187244 counting only the distinct ones).

The product of its digits is 1024, while the sum is 27.

The square root of 128221812 is about 11323.5070539122. The cubic root of 128221812 is about 504.2593619724.

The spelling of 128221812 in words is "one hundred twenty-eight million, two hundred twenty-one thousand, eight hundred twelve".