642642105397 has 2 divisors, whose sum is σ = 642642105398. Its totient is φ = 642642105396.

The previous prime is 642642105377. The next prime is 642642105403. The reversal of 642642105397 is 793501246246.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 616203020196 + 26439085201 = 784986^2 + 162601^2 .

It is a cyclic number.

It is not a de Polignac number, because 642642105397 - 2¹¹ = 642642103349 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 642642105397.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (642642105377) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 321321052698 + 321321052699.

It is an arithmetic number, because the mean of its divisors is an integer number (321321052699).

Almost surely, 2^642642105397 is an apocalyptic number.

It is an amenable number.

642642105397 is a deficient number, since it is larger than the sum of its proper divisors (1).

642642105397 is an equidigital number, since it uses as much as digits as its factorization.

642642105397 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 2177280, while the sum is 49.

The spelling of 642642105397 in words is "six hundred forty-two billion, six hundred forty-two million, one hundred five thousand, three hundred ninety-seven".