1178465221561 has 2 divisors, whose sum is σ = 1178465221562. Its totient is φ = 1178465221560.

The previous prime is 1178465221553. The next prime is 1178465221603. The reversal of 1178465221561 is 1651225648711.

It is a happy number.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 776231481600 + 402233739961 = 881040^2 + 634219^2 .

It is a cyclic number.

It is not a de Polignac number, because 1178465221561 - 2³ = 1178465221553 is a prime.

It is not a weakly prime, because it can be changed into another prime (1178465221261) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 589232610780 + 589232610781.

It is an arithmetic number, because the mean of its divisors is an integer number (589232610781).

Almost surely, 2^{1178465221561} is an apocalyptic number.

It is an amenable number.

1178465221561 is a deficient number, since it is larger than the sum of its proper divisors (1).

1178465221561 is an equidigital number, since it uses as much as digits as its factorization.

1178465221561 is an evil number, because the sum of its binary digits is even.

The product of its digits is 806400, while the sum is 49.

The spelling of 1178465221561 in words is "one trillion, one hundred seventy-eight billion, four hundred sixty-five million, two hundred twenty-one thousand, five hundred sixty-one".