2021013123121 has 2 divisors, whose sum is σ = 2021013123122. Its totient is φ = 2021013123120.

The previous prime is 2021013123119. The next prime is 2021013123133. The reversal of 2021013123121 is 1213213101202.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 1911759736896 + 109253386225 = 1382664^2 + 330535^2 .

It is a cyclic number.

It is not a de Polignac number, because 2021013123121 - 2¹ = 2021013123119 is a prime.

Together with 2021013123119, it forms a pair of twin primes.

It is not a weakly prime, because it can be changed into another prime (2021013123721) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 1010506561560 + 1010506561561.

It is an arithmetic number, because the mean of its divisors is an integer number (1010506561561).

Almost surely, 2^{2021013123121} is an apocalyptic number.

It is an amenable number.

2021013123121 is a deficient number, since it is larger than the sum of its proper divisors (1).

2021013123121 is an equidigital number, since it uses as much as digits as its factorization.

2021013123121 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 144, while the sum is 19.

Adding to 2021013123121 its reverse (1213213101202), we get a palindrome (3234226224323).

The spelling of 2021013123121 in words is "two trillion, twenty-one billion, thirteen million, one hundred twenty-three thousand, one hundred twenty-one".