212231561 has 2 divisors, whose sum is σ = 212231562. Its totient is φ = 212231560.

The previous prime is 212231543. The next prime is 212231597. The reversal of 212231561 is 165132212.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 211149961 + 1081600 = 14531^2 + 1040^2 .

It is a cyclic number.

It is not a de Polignac number, because 212231561 - 2¹⁴ = 212215177 is a prime.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (212231521) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 106115780 + 106115781.

It is an arithmetic number, because the mean of its divisors is an integer number (106115781).

Almost surely, 2^212231561 is an apocalyptic number.

It is an amenable number.

212231561 is a deficient number, since it is larger than the sum of its proper divisors (1).

212231561 is an equidigital number, since it uses as much as digits as its factorization.

212231561 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 720, while the sum is 23.

The square root of 212231561 is about 14568.1694457471. The cubic root of 212231561 is about 596.4902136624.

Adding to 212231561 its reverse (165132212), we get a palindrome (377363773).

The spelling of 212231561 in words is "two hundred twelve million, two hundred thirty-one thousand, five hundred sixty-one".