2121221221020 has 144 divisors (see below), whose sum is σ = 7020896762880. Its totient is φ = 514119484800.

The previous prime is 2121221220931. The next prime is 2121221221037. The reversal of 2121221221020 is 201221221212.

It is a happy number.

2121221221020 is a `hidden beast` number, since 212 + 1 + 221 + 2 + 210 + 20 = 666.

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 = 2121221220984 and 2121221221002.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 8829085 + ... + 9066155.

It is an arithmetic number, because the mean of its divisors is an integer number (48756227520).

Almost surely, 2^{2121221221020} is an apocalyptic number.

2121221221020 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 2121221221020, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (3510448381440).

2121221221020 is an abundant number, since it is smaller than the sum of its proper divisors (4899675541860).

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

2121221221020 is a wasteful number, since it uses less digits than its factorization.

2121221221020 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 241616 (or 241611 counting only the distinct ones).

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

Adding to 2121221221020 its reverse (201221221212), we get a palindrome (2322442442232).

The spelling of 2121221221020 in words is "two trillion, one hundred twenty-one billion, two hundred twenty-one million, two hundred twenty-one thousand, twenty".