1212128220 has 48 divisors (see below), whose sum is σ = 3593606688. Its totient is φ = 304220160.

The previous prime is 1212128219. The next prime is 1212128227. The reversal of 1212128220 is 228212121.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1212128227) 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, 593161 + ... + 595200.

It is an arithmetic number, because the mean of its divisors is an integer number (74866806).

Almost surely, 2^1212128220 is an apocalyptic number.

1212128220 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

1212128220 is an abundant number, since it is smaller than the sum of its proper divisors (2381478468).

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

1212128220 is a wasteful number, since it uses less digits than its factorization.

1212128220 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1188390 (or 1188388 counting only the distinct ones).

The product of its (nonzero) digits is 256, while the sum is 21.

The square root of 1212128220 is about 34815.6318339909. The cubic root of 1212128220 is about 1066.2266190499.

The spelling of 1212128220 in words is "one billion, two hundred twelve million, one hundred twenty-eight thousand, two hundred twenty".