1121643121561 has 2 divisors, whose sum is σ = 1121643121562. Its totient is φ = 1121643121560.

The previous prime is 1121643121507. The next prime is 1121643121579. The reversal of 1121643121561 is 1651213461211.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 865272040000 + 256371081561 = 930200^2 + 506331^2 .

It is a cyclic number.

It is not a de Polignac number, because 1121643121561 - 2¹³ = 1121643113369 is a prime.

It is a super-3 number, since 3×1121643121561³ (a number of 37 digits) contains 333 as substring.

It is not a weakly prime, because it can be changed into another prime (1121643121061) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 560821560780 + 560821560781.

It is an arithmetic number, because the mean of its divisors is an integer number (560821560781).

Almost surely, 2^{1121643121561} is an apocalyptic number.

It is an amenable number.

1121643121561 is a deficient number, since it is larger than the sum of its proper divisors (1).

1121643121561 is an equidigital number, since it uses as much as digits as its factorization.

1121643121561 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 8640, while the sum is 34.

Adding to 1121643121561 its reverse (1651213461211), we get a palindrome (2772856582772).

The spelling of 1121643121561 in words is "one trillion, one hundred twenty-one billion, six hundred forty-three million, one hundred twenty-one thousand, five hundred sixty-one".