1211065381 has 2 divisors, whose sum is σ = 1211065382. Its totient is φ = 1211065380.

The previous prime is 1211065379. The next prime is 1211065553. The reversal of 1211065381 is 1835601121.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 1209996225 + 1069156 = 34785^2 + 1034^2 .

It is a cyclic number.

It is not a de Polignac number, because 1211065381 - 2¹ = 1211065379 is a prime.

It is a super-2 number, since 2×1211065381² = 2933358714113350322, which contains 22 as substring.

Together with 1211065379, it forms a pair of twin primes.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (1211065351) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 605532690 + 605532691.

It is an arithmetic number, because the mean of its divisors is an integer number (605532691).

Almost surely, 2^1211065381 is an apocalyptic number.

It is an amenable number.

1211065381 is a deficient number, since it is larger than the sum of its proper divisors (1).

1211065381 is an equidigital number, since it uses as much as digits as its factorization.

1211065381 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 1440, while the sum is 28.

The square root of 1211065381 is about 34800.3646676296. The cubic root of 1211065381 is about 1065.9148922334.

The spelling of 1211065381 in words is "one billion, two hundred eleven million, sixty-five thousand, three hundred eighty-one".