2121023221021 has 12 divisors (see below), whose sum is σ = 2198291368572. Its totient is φ = 2045732484224.

The previous prime is 2121023221019. The next prime is 2121023221081. The reversal of 2121023221021 is 1201223201212.

It can be written as a sum of positive squares in 2 ways, for example, as 1590436265625 + 530586955396 = 1261125^2 + 728414^2 .

It is not a de Polignac number, because 2121023221021 - 2¹ = 2121023221019 is a prime.

It is a super-2 number, since 2×2121023221021² (a number of 25 digits) contains 22 as substring.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 2121023221021.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (2121023221001) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 5563756 + ... + 5932741.

It is an arithmetic number, because the mean of its divisors is an integer number (183190947381).

Almost surely, 2^{2121023221021} is an apocalyptic number.

It is an amenable number.

2121023221021 is a deficient number, since it is larger than the sum of its proper divisors (77268147551).

2121023221021 is an equidigital number, since it uses as much as digits as its factorization.

2121023221021 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 11496668 (or 11496609 counting only the distinct ones).

The product of its (nonzero) digits is 192, while the sum is 19.

Adding to 2121023221021 its reverse (1201223201212), we get a palindrome (3322246422233).

The spelling of 2121023221021 in words is "two trillion, one hundred twenty-one billion, twenty-three million, two hundred twenty-one thousand, twenty-one".