212049781 has 2 divisors, whose sum is σ = 212049782. Its totient is φ = 212049780.

The previous prime is 212049763. The next prime is 212049787. The reversal of 212049781 is 187940212.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 195720100 + 16329681 = 13990^2 + 4041^2 .

It is a cyclic number.

It is not a de Polignac number, because 212049781 - 2⁵ = 212049749 is a prime.

It is a super-2 number, since 2×212049781² = 89930219244295922, which contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (212049787) 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, 106024890 + 106024891.

It is an arithmetic number, because the mean of its divisors is an integer number (106024891).

Almost surely, 2^212049781 is an apocalyptic number.

It is an amenable number.

212049781 is a deficient number, since it is larger than the sum of its proper divisors (1).

212049781 is an equidigital number, since it uses as much as digits as its factorization.

212049781 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 8064, while the sum is 34.

The square root of 212049781 is about 14561.9291647776. The cubic root of 212049781 is about 596.3198636249.

Adding to 212049781 its reverse (187940212), we get a palindrome (399989993).

The spelling of 212049781 in words is "two hundred twelve million, forty-nine thousand, seven hundred eighty-one".