221000212121000 has 128 divisors (see below), whose sum is σ = 557280120852000. Its totient is φ = 81547391692800.

The previous prime is 221000212120999. The next prime is 221000212121057. The reversal of 221000212121000 is 121212000122.

It can be written as a sum of positive squares in 16 ways, for example, as 130995487246276 + 90004724874724 = 11445326^2 + 9487082^2 .

It is an unprimeable number.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 14649584 + ... + 25624416.

Almost surely, 2^{221000212121000} is an apocalyptic number.

221000212121000 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 221000212121000, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (278640060426000).

221000212121000 is an abundant number, since it is smaller than the sum of its proper divisors (336279908731000).

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

221000212121000 is a wasteful number, since it uses less digits than its factorization.

221000212121000 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 10976416 (or 10976402 counting only the distinct ones).

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

Adding to 221000212121000 its reverse (121212000122), we get a palindrome (221121424121122).

The spelling of 221000212121000 in words is "two hundred twenty-one trillion, two hundred twelve million, one hundred twenty-one thousand".