1221110012100 has 288 divisors, whose sum is σ = 3962462386176. Its totient is φ = 287733081600.

The previous prime is 1221110012029. The next prime is 1221110012197. The reversal of 1221110012100 is 12100111221.

It is a super-2 number, since 2×1221110012100² (a number of 25 digits) contains 22 as substring.

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 95 ways as a sum of consecutive naturals, for example, 134671767 + ... + 134680833.

It is an arithmetic number, because the mean of its divisors is an integer number (13758549952).

Almost surely, 2^{1221110012100} is an apocalyptic number.

1221110012100 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 1221110012100, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1981231193088).

1221110012100 is an abundant number, since it is smaller than the sum of its proper divisors (2741352374076).

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

1221110012100 is a wasteful number, since it uses less digits than its factorization.

1221110012100 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 10235 (or 10228 counting only the distinct ones).

The product of its (nonzero) digits is 8, while the sum is 12.

Adding to 1221110012100 its reverse (12100111221), we get a palindrome (1233210123321).

The spelling of 1221110012100 in words is "one trillion, two hundred twenty-one billion, one hundred ten million, twelve thousand, one hundred".