2100100081 has 2 divisors, whose sum is σ = 2100100082. Its totient is φ = 2100100080.

The previous prime is 2100100033. The next prime is 2100100097. The reversal of 2100100081 is 1800010012.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 1280995681 + 819104400 = 35791^2 + 28620^2 .

It is a cyclic number.

It is not a de Polignac number, because 2100100081 - 2⁹ = 2100099569 is a prime.

It is a super-2 number, since 2×2100100081² = 8820840700432413122, which contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (2100100181) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 1050050040 + 1050050041.

It is an arithmetic number, because the mean of its divisors is an integer number (1050050041).

Almost surely, 2^2100100081 is an apocalyptic number.

It is an amenable number.

2100100081 is a deficient number, since it is larger than the sum of its proper divisors (1).

2100100081 is an equidigital number, since it uses as much as digits as its factorization.

2100100081 is an odious number, because the sum of its binary digits is odd.

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

The square root of 2100100081 is about 45826.8489097821. The cubic root of 2100100081 is about 1280.5995077823.

Adding to 2100100081 its reverse (1800010012), we get a palindrome (3900110093).

The spelling of 2100100081 in words is "two billion, one hundred million, one hundred thousand, eighty-one".