2212781 has 2 divisors, whose sum is σ = 2212782. Its totient is φ = 2212780.

The previous prime is 2212753. The next prime is 2212783. The reversal of 2212781 is 1872122.

2212781 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 2128681 + 84100 = 1459^2 + 290^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-2212781 is a prime.

It is a super-2 number, since 2×2212781² = 9792799507922, which contains 22 as substring.

Together with 2212783, it forms a pair of twin primes.

It is a Chen prime.

It is an Ulam number.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (2212783) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 1106390 + 1106391.

It is an arithmetic number, because the mean of its divisors is an integer number (1106391).

2^2212781 is an apocalyptic number.

It is an amenable number.

2212781 is a deficient number, since it is larger than the sum of its proper divisors (1).

2212781 is an equidigital number, since it uses as much as digits as its factorization.

2212781 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 448, while the sum is 23.

The square root of 2212781 is about 1487.5419321821. The cubic root of 2212781 is about 130.3105200239.

It can be divided in two parts, 22 and 12781, that multiplied together give a palindrome (281182).

The spelling of 2212781 in words is "two million, two hundred twelve thousand, seven hundred eighty-one".