1321565630621 has 2 divisors, whose sum is σ = 1321565630622. Its totient is φ = 1321565630620.

The previous prime is 1321565630617. The next prime is 1321565630641. The reversal of 1321565630621 is 1260365651231.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 1201928505625 + 119637124996 = 1096325^2 + 345886^2 .

It is a cyclic number.

It is not a de Polignac number, because 1321565630621 - 2² = 1321565630617 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (1321565630641) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 660782815310 + 660782815311.

It is an arithmetic number, because the mean of its divisors is an integer number (660782815311).

Almost surely, 2^{1321565630621} is an apocalyptic number.

It is an amenable number.

1321565630621 is a deficient number, since it is larger than the sum of its proper divisors (1).

1321565630621 is an equidigital number, since it uses as much as digits as its factorization.

1321565630621 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 194400, while the sum is 41.

The spelling of 1321565630621 in words is "one trillion, three hundred twenty-one billion, five hundred sixty-five million, six hundred thirty thousand, six hundred twenty-one".