2101000100021 has 2 divisors, whose sum is σ = 2101000100022. Its totient is φ = 2101000100020.

The previous prime is 2101000099999. The next prime is 2101000100041. The reversal of 2101000100021 is 1200010001012.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 1831001391025 + 269998708996 = 1353145^2 + 519614^2 .

It is a cyclic number.

It is not a de Polignac number, because 2101000100021 - 2¹⁰ = 2101000098997 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 2101000099981 and 2101000100008.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (2101000100041) 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, 1050500050010 + 1050500050011.

It is an arithmetic number, because the mean of its divisors is an integer number (1050500050011).

Almost surely, 2^{2101000100021} is an apocalyptic number.

It is an amenable number.

2101000100021 is a deficient number, since it is larger than the sum of its proper divisors (1).

2101000100021 is an equidigital number, since it uses as much as digits as its factorization.

2101000100021 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 4, while the sum is 8.

Adding to 2101000100021 its reverse (1200010001012), we get a palindrome (3301010101033).

Subtracting from 2101000100021 its reverse (1200010001012), we obtain a palindrome (900990099009).

The spelling of 2101000100021 in words is "two trillion, one hundred one billion, one hundred thousand, twenty-one".