1305434621681 has 2 divisors, whose sum is σ = 1305434621682. Its totient is φ = 1305434621680.

The previous prime is 1305434621629. The next prime is 1305434621749. The reversal of 1305434621681 is 1861264345031.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 1211727616225 + 93707005456 = 1100785^2 + 306116^2 .

It is a cyclic number.

It is not a de Polignac number, because 1305434621681 - 2¹⁴ = 1305434605297 is a prime.

It is a super-2 number, since 2×1305434621681² (a number of 25 digits) contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (1305434621581) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 652717310840 + 652717310841.

It is an arithmetic number, because the mean of its divisors is an integer number (652717310841).

Almost surely, 2^{1305434621681} is an apocalyptic number.

It is an amenable number.

1305434621681 is a deficient number, since it is larger than the sum of its proper divisors (1).

1305434621681 is an equidigital number, since it uses as much as digits as its factorization.

1305434621681 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 414720, while the sum is 44.

The spelling of 1305434621681 in words is "one trillion, three hundred five billion, four hundred thirty-four million, six hundred twenty-one thousand, six hundred eighty-one".