1211020121 has 2 divisors, whose sum is σ = 1211020122. Its totient is φ = 1211020120.

The previous prime is 1211020117. The next prime is 1211020123. The reversal of 1211020121 is 1210201121.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 1191975625 + 19044496 = 34525^2 + 4364^2 .

It is an emirp because it is prime and its reverse (1210201121) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 1211020121 - 2² = 1211020117 is a prime.

Together with 1211020123, it forms a pair of twin primes.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (1211020123) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 605510060 + 605510061.

It is an arithmetic number, because the mean of its divisors is an integer number (605510061).

Almost surely, 2^1211020121 is an apocalyptic number.

It is an amenable number.

1211020121 is a deficient number, since it is larger than the sum of its proper divisors (1).

1211020121 is an equidigital number, since it uses as much as digits as its factorization.

1211020121 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 8, while the sum is 11.

The square root of 1211020121 is about 34799.7143810118. The cubic root of 1211020121 is about 1065.9016135919.

Adding to 1211020121 its reverse (1210201121), we get a palindrome (2421221242).

The spelling of 1211020121 in words is "one billion, two hundred eleven million, twenty thousand, one hundred twenty-one".