2102011981 has 2 divisors, whose sum is σ = 2102011982. Its totient is φ = 2102011980.

The previous prime is 2102011979. The next prime is 2102012027. The reversal of 2102011981 is 1891102012.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 2098556100 + 3455881 = 45810^2 + 1859^2 .

It is a cyclic number.

It is not a de Polignac number, because 2102011981 - 2¹ = 2102011979 is a prime.

It is a super-2 number, since 2×2102011981² = 8836908736535088722, which contains 22 as substring.

Together with 2102011979, it forms a pair of twin primes.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (2102051981) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 1051005990 + 1051005991.

It is an arithmetic number, because the mean of its divisors is an integer number (1051005991).

Almost surely, 2^2102011981 is an apocalyptic number.

It is an amenable number.

2102011981 is a deficient number, since it is larger than the sum of its proper divisors (1).

2102011981 is an equidigital number, since it uses as much as digits as its factorization.

2102011981 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 288, while the sum is 25.

The square root of 2102011981 is about 45847.7042064267. The cubic root of 2102011981 is about 1280.9880028526.

Adding to 2102011981 its reverse (1891102012), we get a palindrome (3993113993).

The spelling of 2102011981 in words is "two billion, one hundred two million, eleven thousand, nine hundred eighty-one".