645304135006561 has 2 divisors, whose sum is σ = 645304135006562. Its totient is φ = 645304135006560.

The previous prime is 645304135006493. The next prime is 645304135006691. The reversal of 645304135006561 is 165600531403546.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 643321335888400 + 1982799118161 = 25363780^2 + 1408119^2 .

It is a cyclic number.

It is not a de Polignac number, because 645304135006561 - 2²¹ = 645304132909409 is a prime.

It is not a weakly prime, because it can be changed into another prime (645304135046561) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 322652067503280 + 322652067503281.

It is an arithmetic number, because the mean of its divisors is an integer number (322652067503281).

Almost surely, 2^{645304135006561} is an apocalyptic number.

It is an amenable number.

645304135006561 is a deficient number, since it is larger than the sum of its proper divisors (1).

645304135006561 is an equidigital number, since it uses as much as digits as its factorization.

645304135006561 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 3888000, while the sum is 49.

The spelling of 645304135006561 in words is "six hundred forty-five trillion, three hundred four billion, one hundred thirty-five million, six thousand, five hundred sixty-one".