1211220993817 has 2 divisors, whose sum is σ = 1211220993818. Its totient is φ = 1211220993816.

The previous prime is 1211220993811. The next prime is 1211220993839. The reversal of 1211220993817 is 7183990221121.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 914173103376 + 297047890441 = 956124^2 + 545021^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-1211220993817 is a prime.

It is not a weakly prime, because it can be changed into another prime (1211220993811) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 605610496908 + 605610496909.

It is an arithmetic number, because the mean of its divisors is an integer number (605610496909).

Almost surely, 2^{1211220993817} is an apocalyptic number.

It is an amenable number.

1211220993817 is a deficient number, since it is larger than the sum of its proper divisors (1).

1211220993817 is an equidigital number, since it uses as much as digits as its factorization.

1211220993817 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 108864, while the sum is 46.

The spelling of 1211220993817 in words is "one trillion, two hundred eleven billion, two hundred twenty million, nine hundred ninety-three thousand, eight hundred seventeen".