1212221122400 has 144 divisors (see below), whose sum is σ = 3002720876064. Its totient is φ = 477792276480.

The previous prime is 1212221122309. The next prime is 1212221122423. The reversal of 1212221122400 is 42211222121.

It is a happy number.

It is a Harshad number since it is a multiple of its sum of digits (20).

It is a congruent number.

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 23 ways as a sum of consecutive naturals, for example, 65223509 + ... + 65242091.

It is an arithmetic number, because the mean of its divisors is an integer number (20852228306).

Almost surely, 2^{1212221122400} is an apocalyptic number.

1212221122400 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 1212221122400, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1501360438032).

1212221122400 is an abundant number, since it is smaller than the sum of its proper divisors (1790499753664).

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

1212221122400 is a wasteful number, since it uses less digits than its factorization.

1212221122400 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 19793 (or 19780 counting only the distinct ones).

The product of its (nonzero) digits is 256, while the sum is 20.

Adding to 1212221122400 its reverse (42211222121), we get a palindrome (1254432344521).

The spelling of 1212221122400 in words is "one trillion, two hundred twelve billion, two hundred twenty-one million, one hundred twenty-two thousand, four hundred".