312212221 has 2 divisors, whose sum is σ = 312212222. Its totient is φ = 312212220.

The previous prime is 312212183. The next prime is 312212233. The reversal of 312212221 is 122212213.

It is a happy number.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 264062500 + 48149721 = 16250^2 + 6939^2 .

It is an emirp because it is prime and its reverse (122212213) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 312212221 - 2⁷ = 312212093 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 312212195 and 312212204.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (312212321) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 156106110 + 156106111.

It is an arithmetic number, because the mean of its divisors is an integer number (156106111).

Almost surely, 2^312212221 is an apocalyptic number.

It is an amenable number.

312212221 is a deficient number, since it is larger than the sum of its proper divisors (1).

312212221 is an equidigital number, since it uses as much as digits as its factorization.

312212221 is an evil number, because the sum of its binary digits is even.

The product of its digits is 96, while the sum is 16.

The square root of 312212221 is about 17669.5280355758. The cubic root of 312212221 is about 678.3960328698.

Adding to 312212221 its reverse (122212213), we get a palindrome (434424434).

The spelling of 312212221 in words is "three hundred twelve million, two hundred twelve thousand, two hundred twenty-one".