221212121000 has 256 divisors, whose sum is σ = 568215648000. Its totient is φ = 80117683200.

The previous prime is 221212120999. The next prime is 221212121021. The reversal of 221212121000 is 121212122.

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, 151618271 + ... + 151619729.

It is an arithmetic number, because the mean of its divisors is an integer number (2219592375).

Almost surely, 2^221212121000 is an apocalyptic number.

221212121000 is a gapful number since it is divisible by the number (20) 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 221212121000, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (284107824000).

221212121000 is an abundant number, since it is smaller than the sum of its proper divisors (347003527000).

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

221212121000 is a wasteful number, since it uses less digits than its factorization.

221212121000 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1709 (or 1695 counting only the distinct ones).

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

Adding to 221212121000 its reverse (121212122), we get a palindrome (221333333122).

The spelling of 221212121000 in words is "two hundred twenty-one billion, two hundred twelve million, one hundred twenty-one thousand".