1221001222100 has 144 divisors (see below), whose sum is σ = 3065273559936. Its totient is φ = 417226752000.

The previous prime is 1221001222087. The next prime is 1221001222109. The reversal of 1221001222100 is 12221001221.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1221001222109) by changing a digit.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 11935769 + ... + 12037631.

It is an arithmetic number, because the mean of its divisors is an integer number (21286621944).

Almost surely, 2^{1221001222100} is an apocalyptic number.

1221001222100 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 1221001222100, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1532636779968).

1221001222100 is an abundant number, since it is smaller than the sum of its proper divisors (1844272337836).

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

1221001222100 is a wasteful number, since it uses less digits than its factorization.

1221001222100 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 102546 (or 102539 counting only the distinct ones).

The product of its (nonzero) digits is 32, while the sum is 14.

Adding to 1221001222100 its reverse (12221001221), we get a palindrome (1233222223321).

The spelling of 1221001222100 in words is "one trillion, two hundred twenty-one billion, one million, two hundred twenty-two thousand, one hundred".