1217042465861 has 2 divisors, whose sum is σ = 1217042465862. Its totient is φ = 1217042465860.

The previous prime is 1217042465857. The next prime is 1217042465867. The reversal of 1217042465861 is 1685642407121.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 1199888015236 + 17154450625 = 1095394^2 + 130975^2 .

It is a cyclic number.

It is not a de Polignac number, because 1217042465861 - 2² = 1217042465857 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (1217042465867) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 608521232930 + 608521232931.

It is an arithmetic number, because the mean of its divisors is an integer number (608521232931).

Almost surely, 2^{1217042465861} is an apocalyptic number.

It is an amenable number.

1217042465861 is a deficient number, since it is larger than the sum of its proper divisors (1).

1217042465861 is an equidigital number, since it uses as much as digits as its factorization.

1217042465861 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 645120, while the sum is 47.

The spelling of 1217042465861 in words is "one trillion, two hundred seventeen billion, forty-two million, four hundred sixty-five thousand, eight hundred sixty-one".