2102111020021 has 4 divisors (see below), whose sum is σ = 2225764609452. Its totient is φ = 1978457430592.

The previous prime is 2102111020007. The next prime is 2102111020043. The reversal of 2102111020021 is 1200201112012.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 1064014943121 + 1038096076900 = 1031511^2 + 1018870^2 .

It is a cyclic number.

It is not a de Polignac number, because 2102111020021 - 2⁷ = 2102111019893 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 2102111019983 and 2102111020010.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (2102111020091) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 61826794690 + ... + 61826794723.

It is an arithmetic number, because the mean of its divisors is an integer number (556441152363).

Almost surely, 2^{2102111020021} is an apocalyptic number.

It is an amenable number.

2102111020021 is a deficient number, since it is larger than the sum of its proper divisors (123653589431).

2102111020021 is a wasteful number, since it uses less digits than its factorization.

2102111020021 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 123653589430.

The product of its (nonzero) digits is 16, while the sum is 13.

Adding to 2102111020021 its reverse (1200201112012), we get a palindrome (3302312132033).

The spelling of 2102111020021 in words is "two trillion, one hundred two billion, one hundred eleven million, twenty thousand, twenty-one".