1212221100 has 36 divisors (see below), whose sum is σ = 3507360584. Its totient is φ = 323258880.

The previous prime is 1212221093. The next prime is 1212221119. The reversal of 1212221100 is 11222121.

It is a Harshad number since it is a multiple of its sum of digits (12).

It is an unprimeable number.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 2020069 + ... + 2020668.

Almost surely, 2^1212221100 is an apocalyptic number.

1212221100 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

1212221100 is an abundant number, since it is smaller than the sum of its proper divisors (2295139484).

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

1212221100 is a wasteful number, since it uses less digits than its factorization.

1212221100 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4040754 (or 4040747 counting only the distinct ones).

The product of its (nonzero) digits is 16, while the sum is 12.

The square root of 1212221100 is about 34816.9656920301. The cubic root of 1212221100 is about 1066.2538517572.

Adding to 1212221100 its reverse (11222121), we get a palindrome (1223443221).

The spelling of 1212221100 in words is "one billion, two hundred twelve million, two hundred twenty-one thousand, one hundred".