2105042021 has 2 divisors, whose sum is σ = 2105042022. Its totient is φ = 2105042020.

The previous prime is 2105041957. The next prime is 2105042039. The reversal of 2105042021 is 1202405012.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 1514065921 + 590976100 = 38911^2 + 24310^2 .

It is a cyclic number.

It is not a de Polignac number, because 2105042021 - 2⁶ = 2105041957 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (2105044021) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 1052521010 + 1052521011.

It is an arithmetic number, because the mean of its divisors is an integer number (1052521011).

Almost surely, 2^2105042021 is an apocalyptic number.

It is an amenable number.

2105042021 is a deficient number, since it is larger than the sum of its proper divisors (1).

2105042021 is an equidigital number, since it uses as much as digits as its factorization.

2105042021 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 160, while the sum is 17.

The square root of 2105042021 is about 45880.7369273860. The cubic root of 2105042021 is about 1281.6032199854.

Adding to 2105042021 its reverse (1202405012), we get a palindrome (3307447033).

The spelling of 2105042021 in words is "two billion, one hundred five million, forty-two thousand, twenty-one".