212231521 has 2 divisors, whose sum is σ = 212231522. Its totient is φ = 212231520.

The previous prime is 212231489. The next prime is 212231533. The reversal of 212231521 is 125132212.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 115799121 + 96432400 = 10761^2 + 9820^2 .

It is a cyclic number.

It is not a de Polignac number, because 212231521 - 2⁵ = 212231489 is a prime.

It is not a weakly prime, because it can be changed into another prime (212231561) 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, 106115760 + 106115761.

It is an arithmetic number, because the mean of its divisors is an integer number (106115761).

Almost surely, 2^212231521 is an apocalyptic number.

It is an amenable number.

212231521 is a deficient number, since it is larger than the sum of its proper divisors (1).

212231521 is an equidigital number, since it uses as much as digits as its factorization.

212231521 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 240, while the sum is 19.

The square root of 212231521 is about 14568.1680728910. The cubic root of 212231521 is about 596.4901761882.

Adding to 212231521 its reverse (125132212), we get a palindrome (337363733).

The spelling of 212231521 in words is "two hundred twelve million, two hundred thirty-one thousand, five hundred twenty-one".