2001221212122 has 144 divisors (see below), whose sum is σ = 4883026861440. Its totient is φ = 591622162560.

The previous prime is 2001221212117. The next prime is 2001221212157. The reversal of 2001221212122 is 2212121221002.

It is a happy number.

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

It is a junction number, because it is equal to n+sod(n) for n = 2001221212095 and 2001221212104.

It is an unprimeable number.

It is a polite number, since it can be written in 71 ways as a sum of consecutive naturals, for example, 32009329 + ... + 32071787.

It is an arithmetic number, because the mean of its divisors is an integer number (33909908760).

Almost surely, 2^{2001221212122} is an apocalyptic number.

2001221212122 is a gapful number since it is divisible by the number (22) formed by its first and last digit.

It is a practical number, because each smaller number is the sum of distinct divisors of 2001221212122, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (2441513430720).

2001221212122 is an abundant number, since it is smaller than the sum of its proper divisors (2881805649318).

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

2001221212122 is a wasteful number, since it uses less digits than its factorization.

2001221212122 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 62849 (or 62835 counting only the distinct ones).

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

Adding to 2001221212122 its reverse (2212121221002), we get a palindrome (4213342433124).

The spelling of 2001221212122 in words is "two trillion, one billion, two hundred twenty-one million, two hundred twelve thousand, one hundred twenty-two".