1221210212100 has 36 divisors (see below), whose sum is σ = 3533368214544. Its totient is φ = 325656056480.

The previous prime is 1221210212051. The next prime is 1221210212149. The reversal of 1221210212100 is 12120121221.

It is an interprime number because it is at equal distance from previous prime (1221210212051) and next prime (1221210212149).

It is a Harshad number since it is a multiple of its sum of digits (15).

It is a self number, because there is not a number n which added to its sum of digits gives 1221210212100.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 2035350054 + ... + 2035350653.

Almost surely, 2^{1221210212100} is an apocalyptic number.

1221210212100 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

1221210212100 is an abundant number, since it is smaller than the sum of its proper divisors (2312158002444).

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

1221210212100 is a wasteful number, since it uses less digits than its factorization.

1221210212100 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4070700724 (or 4070700717 counting only the distinct ones).

The product of its (nonzero) digits is 32, while the sum is 15.

Adding to 1221210212100 its reverse (12120121221), we get a palindrome (1233330333321).

The spelling of 1221210212100 in words is "one trillion, two hundred twenty-one billion, two hundred ten million, two hundred twelve thousand, one hundred".