2100202120021 has 2 divisors, whose sum is σ = 2100202120022. Its totient is φ = 2100202120020.

The previous prime is 2100202120007. The next prime is 2100202120063. The reversal of 2100202120021 is 1200212020012.

It is a happy number.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 1949056119396 + 151146000625 = 1396086^2 + 388775^2 .

It is a cyclic number.

It is not a de Polignac number, because 2100202120021 - 2⁷ = 2100202119893 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 2100202119983 and 2100202120010.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (2100202120001) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 1050101060010 + 1050101060011.

It is an arithmetic number, because the mean of its divisors is an integer number (1050101060011).

Almost surely, 2^{2100202120021} is an apocalyptic number.

It is an amenable number.

2100202120021 is a deficient number, since it is larger than the sum of its proper divisors (1).

2100202120021 is an equidigital number, since it uses as much as digits as its factorization.

2100202120021 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 32, while the sum is 13.

Adding to 2100202120021 its reverse (1200212020012), we get a palindrome (3300414140033).

The spelling of 2100202120021 in words is "two trillion, one hundred billion, two hundred two million, one hundred twenty thousand, twenty-one".