1221211212100 has 72 divisors (see below), whose sum is σ = 2900060509248. Its totient is φ = 442675804800.

The previous prime is 1221211211959. The next prime is 1221211212187. The reversal of 1221211212100 is 12121121221.

It is an unprimeable number.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 1402392 + ... + 2099791.

It is an arithmetic number, because the mean of its divisors is an integer number (40278618184).

Almost surely, 2^{1221211212100} is an apocalyptic number.

1221211212100 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

1221211212100 is an abundant number, since it is smaller than the sum of its proper divisors (1678849297148).

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

1221211212100 is a wasteful number, since it uses less digits than its factorization.

1221211212100 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3502525 (or 3502518 counting only the distinct ones).

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

Adding to 1221211212100 its reverse (12121121221), we get a palindrome (1233332333321).

The spelling of 1221211212100 in words is "one trillion, two hundred twenty-one billion, two hundred eleven million, two hundred twelve thousand, one hundred".