2121010081 has 2 divisors, whose sum is σ = 2121010082. Its totient is φ = 2121010080.

The previous prime is 2121010079. The next prime is 2121010123. The reversal of 2121010081 is 1800101212.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 1663905681 + 457104400 = 40791^2 + 21380^2 .

It is a cyclic number.

It is not a de Polignac number, because 2121010081 - 2¹ = 2121010079 is a prime.

It is a super-2 number, since 2×2121010081² = 8997367527407253122, which contains 22 as substring.

Together with 2121010079, it forms a pair of twin primes.

It is not a weakly prime, because it can be changed into another prime (2121050081) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 1060505040 + 1060505041.

It is an arithmetic number, because the mean of its divisors is an integer number (1060505041).

Almost surely, 2^2121010081 is an apocalyptic number.

It is an amenable number.

2121010081 is a deficient number, since it is larger than the sum of its proper divisors (1).

2121010081 is an equidigital number, since it uses as much as digits as its factorization.

2121010081 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 32, while the sum is 16.

The square root of 2121010081 is about 46054.4252054024. The cubic root of 2121010081 is about 1284.8356476504.

Adding to 2121010081 its reverse (1800101212), we get a palindrome (3921111293).

The spelling of 2121010081 in words is "two billion, one hundred twenty-one million, ten thousand, eighty-one".