1221021211100 has 18 divisors (see below), whose sum is σ = 2649616028304. Its totient is φ = 488408484400.

The previous prime is 1221021211099. The next prime is 1221021211103. The reversal of 1221021211100 is 11121201221.

It is a super-2 number, since 2×1221021211100² (a number of 25 digits) contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1221021211103) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 6105105956 + ... + 6105106155.

Almost surely, 2^{1221021211100} is an apocalyptic number.

1221021211100 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

1221021211100 is an abundant number, since it is smaller than the sum of its proper divisors (1428594817204).

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

1221021211100 is a wasteful number, since it uses less digits than its factorization.

1221021211100 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 12210212125 (or 12210212118 counting only the distinct ones).

The product of its (nonzero) digits is 16, while the sum is 14.

Adding to 1221021211100 its reverse (11121201221), we get a palindrome (1232142412321).

The spelling of 1221021211100 in words is "one trillion, two hundred twenty-one billion, twenty-one million, two hundred eleven thousand, one hundred".