1309645366021 has 2 divisors, whose sum is σ = 1309645366022. Its totient is φ = 1309645366020.

The previous prime is 1309645365991. The next prime is 1309645366049. The reversal of 1309645366021 is 1206635469031.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 1302771132100 + 6874233921 = 1141390^2 + 82911^2 .

It is a cyclic number.

It is not a de Polignac number, because 1309645366021 - 2¹⁵ = 1309645333253 is a prime.

It is a super-2 number, since 2×1309645366021² (a number of 25 digits) contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (1309645366621) 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, 654822683010 + 654822683011.

It is an arithmetic number, because the mean of its divisors is an integer number (654822683011).

Almost surely, 2^{1309645366021} is an apocalyptic number.

It is an amenable number.

1309645366021 is a deficient number, since it is larger than the sum of its proper divisors (1).

1309645366021 is an equidigital number, since it uses as much as digits as its factorization.

1309645366021 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 699840, while the sum is 46.

The spelling of 1309645366021 in words is "one trillion, three hundred nine billion, six hundred forty-five million, three hundred sixty-six thousand, twenty-one".