1221211211000 has 256 divisors, whose sum is σ = 3181967193600. Its totient is φ = 434957952000.

The previous prime is 1221211210991. The next prime is 1221211211071. The reversal of 1221211211000 is 1121121221.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 63 ways as a sum of consecutive naturals, for example, 131918372 + ... + 131927628.

It is an arithmetic number, because the mean of its divisors is an integer number (12429559350).

Almost surely, 2^{1221211211000} is an apocalyptic number.

1221211211000 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 1221211211000, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1590983596800).

1221211211000 is an abundant number, since it is smaller than the sum of its proper divisors (1960755982600).

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

1221211211000 is a wasteful number, since it uses less digits than its factorization.

1221211211000 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 9535 (or 9521 counting only the distinct ones).

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

Adding to 1221211211000 its reverse (1121121221), we get a palindrome (1222332332221).

The spelling of 1221211211000 in words is "one trillion, two hundred twenty-one billion, two hundred eleven million, two hundred eleven thousand".