2121321031020 has 216 divisors, whose sum is σ = 6838909210224. Its totient is φ = 532140521472.

The previous prime is 2121321030991. The next prime is 2121321031021. The reversal of 2121321031020 is 201301231212.

2121321031020 is a `hidden beast` number, since 2 + 12 + 1 + 321 + 0 + 310 + 20 = 666.

It is a super-3 number, since 3×2121321031020³ (a number of 38 digits) contains 333 as substring.

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 = 2121321030984 and 2121321031002.

It is not an unprimeable number, because it can be changed into a prime (2121321031021) by changing a digit.

It is a polite number, since it can be written in 71 ways as a sum of consecutive naturals, for example, 115111047 + ... + 115129473.

It is an arithmetic number, because the mean of its divisors is an integer number (31661616714).

Almost surely, 2^{2121321031020} is an apocalyptic number.

2121321031020 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 2121321031020, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (3419454605112).

2121321031020 is an abundant number, since it is smaller than the sum of its proper divisors (4717588179204).

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

2121321031020 is a wasteful number, since it uses less digits than its factorization.

2121321031020 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 20689 (or 20667 counting only the distinct ones).

The product of its (nonzero) digits is 144, while the sum is 18.

Adding to 2121321031020 its reverse (201301231212), we get a palindrome (2322622262232).

The spelling of 2121321031020 in words is "two trillion, one hundred twenty-one billion, three hundred twenty-one million, thirty-one thousand, twenty".