2123112781 has 2 divisors, whose sum is σ = 2123112782. Its totient is φ = 2123112780.

The previous prime is 2123112769. The next prime is 2123112793. The reversal of 2123112781 is 1872113212.

It is a balanced prime because it is at equal distance from previous prime (2123112769) and next prime (2123112793).

It can be written as a sum of positive squares in only one way, i.e., 1911875625 + 211237156 = 43725^2 + 14534^2 .

It is a cyclic number.

It is not a de Polignac number, because 2123112781 - 2¹⁹ = 2122588493 is a prime.

It is a super-2 number, since 2×2123112781² = 9015215761691107922, which contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (2123112751) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 1061556390 + 1061556391.

It is an arithmetic number, because the mean of its divisors is an integer number (1061556391).

Almost surely, 2^2123112781 is an apocalyptic number.

It is an amenable number.

2123112781 is a deficient number, since it is larger than the sum of its proper divisors (1).

2123112781 is an equidigital number, since it uses as much as digits as its factorization.

2123112781 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 1344, while the sum is 28.

The square root of 2123112781 is about 46077.2479755465. The cubic root of 2123112781 is about 1285.2600887637.

Adding to 2123112781 its reverse (1872113212), we get a palindrome (3995225993).

The spelling of 2123112781 in words is "two billion, one hundred twenty-three million, one hundred twelve thousand, seven hundred eighty-one".