1221211221100 has 54 divisors (see below), whose sum is σ = 2869557365220. Its totient is φ = 450908752320.

The previous prime is 1221211221089. The next prime is 1221211221121. The reversal of 1221211221100 is 11221121221.

It is an unprimeable number.

It is a polite number, since it can be written in 17 ways as a sum of consecutive naturals, for example, 36113610 + ... + 36147409.

Almost surely, 2^{1221211221100} is an apocalyptic number.

1221211221100 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

1221211221100 is an abundant number, since it is smaller than the sum of its proper divisors (1648346144120).

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

1221211221100 is a wasteful number, since it uses less digits than its factorization.

1221211221100 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 72261059 (or 72261039 counting only the distinct ones).

The product of its (nonzero) digits is 32, while the sum is 16.

Adding to 1221211221100 its reverse (11221121221), we get a palindrome (1232432342321).

The spelling of 1221211221100 in words is "one trillion, two hundred twenty-one billion, two hundred eleven million, two hundred twenty-one thousand, one hundred".