1321565630641 has 2 divisors, whose sum is σ = 1321565630642. Its totient is φ = 1321565630640.

The previous prime is 1321565630621. The next prime is 1321565630657. The reversal of 1321565630641 is 1460365651231.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 1306357561600 + 15208069041 = 1142960^2 + 123321^2 .

It is an emirp because it is prime and its reverse (1460365651231) is a distict prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-1321565630641 is a prime.

It is not a weakly prime, because it can be changed into another prime (1321565630621) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 660782815320 + 660782815321.

It is an arithmetic number, because the mean of its divisors is an integer number (660782815321).

Almost surely, 2^{1321565630641} is an apocalyptic number.

It is an amenable number.

1321565630641 is a deficient number, since it is larger than the sum of its proper divisors (1).

1321565630641 is an equidigital number, since it uses as much as digits as its factorization.

1321565630641 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 388800, while the sum is 43.

The spelling of 1321565630641 in words is "one trillion, three hundred twenty-one billion, five hundred sixty-five million, six hundred thirty thousand, six hundred forty-one".