212123313221 has 2 divisors, whose sum is σ = 212123313222. Its totient is φ = 212123313220.

The previous prime is 212123313179. The next prime is 212123313239. The reversal of 212123313221 is 122313321212.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 205884525025 + 6238788196 = 453745^2 + 78986^2 .

It is a cyclic number.

It is not a de Polignac number, because 212123313221 - 2¹⁴ = 212123296837 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (212123313251) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 106061656610 + 106061656611.

It is an arithmetic number, because the mean of its divisors is an integer number (106061656611).

Almost surely, 2^212123313221 is an apocalyptic number.

It is an amenable number.

212123313221 is a deficient number, since it is larger than the sum of its proper divisors (1).

212123313221 is an equidigital number, since it uses as much as digits as its factorization.

212123313221 is an evil number, because the sum of its binary digits is even.

The product of its digits is 864, while the sum is 23.

Adding to 212123313221 its reverse (122313321212), we get a palindrome (334436634433).

The spelling of 212123313221 in words is "two hundred twelve billion, one hundred twenty-three million, three hundred thirteen thousand, two hundred twenty-one".