1212221222100 has 756 divisors, whose sum is σ = 4580264906784. Its totient is φ = 272647399680.

The previous prime is 1212221222099. The next prime is 1212221222161. The reversal of 1212221222100 is 12221222121.

It is a happy number.

1212221222100 is a `hidden beast` number, since 1 + 212 + 221 + 22 + 210 + 0 = 666.

It is a tau number, because it is divible by the number of its divisors (756).

It is a Harshad number since it is a multiple of its sum of digits (18).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 251 ways as a sum of consecutive naturals, for example, 8135712826 + ... + 8135712974.

It is an arithmetic number, because the mean of its divisors is an integer number (6058551464).

Almost surely, 2^{1212221222100} is an apocalyptic number.

1212221222100 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 1212221222100, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (2290132453392).

1212221222100 is an abundant number, since it is smaller than the sum of its proper divisors (3368043684684).

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

1212221222100 is a wasteful number, since it uses less digits than its factorization.

1212221222100 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 444 (or 273 counting only the distinct ones).

The product of its (nonzero) digits is 128, while the sum is 18.

Adding to 1212221222100 its reverse (12221222121), we get a palindrome (1224442444221).

The spelling of 1212221222100 in words is "one trillion, two hundred twelve billion, two hundred twenty-one million, two hundred twenty-two thousand, one hundred".