1621318325729 has 2 divisors, whose sum is σ = 1621318325730. Its totient is φ = 1621318325728.

The previous prime is 1621318325713. The next prime is 1621318325831. The reversal of 1621318325729 is 9275238131261.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 862712165329 + 758606160400 = 928823^2 + 870980^2 .

It is a cyclic number.

It is not a de Polignac number, because 1621318325729 - 2⁴ = 1621318325713 is a prime.

It is a super-2 number, since 2×1621318325729² (a number of 25 digits) contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (1621318325129) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 810659162864 + 810659162865.

It is an arithmetic number, because the mean of its divisors is an integer number (810659162865).

Almost surely, 2^{1621318325729} is an apocalyptic number.

It is an amenable number.

1621318325729 is a deficient number, since it is larger than the sum of its proper divisors (1).

1621318325729 is an equidigital number, since it uses as much as digits as its factorization.

1621318325729 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 1088640, while the sum is 50.

The spelling of 1621318325729 in words is "one trillion, six hundred twenty-one billion, three hundred eighteen million, three hundred twenty-five thousand, seven hundred twenty-nine".