1755561378121 has 2 divisors, whose sum is σ = 1755561378122. Its totient is φ = 1755561378120.

The previous prime is 1755561378079. The next prime is 1755561378211. The reversal of 1755561378121 is 1218731655571.

Together with next prime (1755561378211) it forms an Ormiston pair, because they use the same digits, order apart.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 1350987782400 + 404573595721 = 1162320^2 + 636061^2 .

It is a cyclic number.

It is not a de Polignac number, because 1755561378121 - 2⁷ = 1755561377993 is a prime.

It is not a weakly prime, because it can be changed into another prime (1755561378421) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 877780689060 + 877780689061.

It is an arithmetic number, because the mean of its divisors is an integer number (877780689061).

Almost surely, 2^{1755561378121} is an apocalyptic number.

It is an amenable number.

1755561378121 is a deficient number, since it is larger than the sum of its proper divisors (1).

1755561378121 is an equidigital number, since it uses as much as digits as its factorization.

1755561378121 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 1764000, while the sum is 52.

The spelling of 1755561378121 in words is "one trillion, seven hundred fifty-five billion, five hundred sixty-one million, three hundred seventy-eight thousand, one hundred twenty-one".