1211203020491 has 2 divisors, whose sum is σ = 1211203020492. Its totient is φ = 1211203020490.

The previous prime is 1211203020431. The next prime is 1211203020557. The reversal of 1211203020491 is 1940203021121.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 1211203020491 - 2¹⁴ = 1211203004107 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 1211203020491.

It is not a weakly prime, because it can be changed into another prime (1211203020421) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 605601510245 + 605601510246.

It is an arithmetic number, because the mean of its divisors is an integer number (605601510246).

Almost surely, 2^{1211203020491} is an apocalyptic number.

1211203020491 is a deficient number, since it is larger than the sum of its proper divisors (1).

1211203020491 is an equidigital number, since it uses as much as digits as its factorization.

1211203020491 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 864, while the sum is 26.

The spelling of 1211203020491 in words is "one trillion, two hundred eleven billion, two hundred three million, twenty thousand, four hundred ninety-one".