2102102120021 has 2 divisors, whose sum is σ = 2102102120022. Its totient is φ = 2102102120020.

The previous prime is 2102102119993. The next prime is 2102102120047. The reversal of 2102102120021 is 1200212012012.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 1787649220900 + 314452899121 = 1337030^2 + 560761^2 .

It is a cyclic number.

It is not a de Polignac number, because 2102102120021 - 2¹⁰ = 2102102118997 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 2102102119978 and 2102102120005.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (2102102120051) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 1051051060010 + 1051051060011.

It is an arithmetic number, because the mean of its divisors is an integer number (1051051060011).

Almost surely, 2^{2102102120021} is an apocalyptic number.

It is an amenable number.

2102102120021 is a deficient number, since it is larger than the sum of its proper divisors (1).

2102102120021 is an equidigital number, since it uses as much as digits as its factorization.

2102102120021 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 32, while the sum is 14.

Adding to 2102102120021 its reverse (1200212012012), we get a palindrome (3302314132033).

The spelling of 2102102120021 in words is "two trillion, one hundred two billion, one hundred two million, one hundred twenty thousand, twenty-one".