2100220019981 has 2 divisors, whose sum is σ = 2100220019982. Its totient is φ = 2100220019980.

The previous prime is 2100220019957. The next prime is 2100220020047. The reversal of 2100220019981 is 1899100220012.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 1458923363881 + 641296656100 = 1207859^2 + 800810^2 .

It is a cyclic number.

It is not a de Polignac number, because 2100220019981 - 2¹⁰ = 2100220018957 is a prime.

It is a super-2 number, since 2×2100220019981² (a number of 25 digits) contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (2100220019941) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 1050110009990 + 1050110009991.

It is an arithmetic number, because the mean of its divisors is an integer number (1050110009991).

Almost surely, 2^{2100220019981} is an apocalyptic number.

It is an amenable number.

2100220019981 is a deficient number, since it is larger than the sum of its proper divisors (1).

2100220019981 is an equidigital number, since it uses as much as digits as its factorization.

2100220019981 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 5184, while the sum is 35.

Adding to 2100220019981 its reverse (1899100220012), we get a palindrome (3999320239993).

The spelling of 2100220019981 in words is "two trillion, one hundred billion, two hundred twenty million, nineteen thousand, nine hundred eighty-one".