212221979 has 2 divisors, whose sum is σ = 212221980. Its totient is φ = 212221978.

The previous prime is 212221969. The next prime is 212221991. The reversal of 212221979 is 979122212.

It is a weak prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-212221979 is a prime.

It is a Sophie Germain prime.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (212221909) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 106110989 + 106110990.

It is an arithmetic number, because the mean of its divisors is an integer number (106110990).

Almost surely, 2^212221979 is an apocalyptic number.

212221979 is a deficient number, since it is larger than the sum of its proper divisors (1).

212221979 is an equidigital number, since it uses as much as digits as its factorization.

212221979 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 9072, while the sum is 35.

The square root of 212221979 is about 14567.8405743610. The cubic root of 212221979 is about 596.4812365885.

The spelling of 212221979 in words is "two hundred twelve million, two hundred twenty-one thousand, nine hundred seventy-nine".