642635661559 has 2 divisors, whose sum is σ = 642635661560. Its totient is φ = 642635661558.

The previous prime is 642635661557. The next prime is 642635661581. The reversal of 642635661559 is 955166536246.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 642635661559 - 2¹ = 642635661557 is a prime.

Together with 642635661557, it forms a pair of twin primes.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (642635661557) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 321317830779 + 321317830780.

It is an arithmetic number, because the mean of its divisors is an integer number (321317830780).

Almost surely, 2^642635661559 is an apocalyptic number.

642635661559 is a deficient number, since it is larger than the sum of its proper divisors (1).

642635661559 is an equidigital number, since it uses as much as digits as its factorization.

642635661559 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 34992000, while the sum is 58.

The spelling of 642635661559 in words is "six hundred forty-two billion, six hundred thirty-five million, six hundred sixty-one thousand, five hundred fifty-nine".