1212122921 has 2 divisors, whose sum is σ = 1212122922. Its totient is φ = 1212122920.

The previous prime is 1212122911. The next prime is 1212122939. The reversal of 1212122921 is 1292212121.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 1201592896 + 10530025 = 34664^2 + 3245^2 .

It is an emirp because it is prime and its reverse (1292212121) is a distict prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-1212122921 is a prime.

It is a super-2 number, since 2×1212122921² = 2938483951227144482, which contains 22 as substring.

It is a Sophie Germain prime.

It is a Curzon number.

It is not a weakly prime, because it can be changed into another prime (1212122911) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 606061460 + 606061461.

It is an arithmetic number, because the mean of its divisors is an integer number (606061461).

Almost surely, 2^1212122921 is an apocalyptic number.

It is an amenable number.

1212122921 is a deficient number, since it is larger than the sum of its proper divisors (1).

1212122921 is an equidigital number, since it uses as much as digits as its factorization.

1212122921 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 288, while the sum is 23.

The square root of 1212122921 is about 34815.5557330340. Note that the first 3 decimals coincide. The cubic root of 1212122921 is about 1066.2250653245.

The spelling of 1212122921 in words is "one billion, two hundred twelve million, one hundred twenty-two thousand, nine hundred twenty-one".