642286439681 has 2 divisors, whose sum is σ = 642286439682. Its totient is φ = 642286439680.

The previous prime is 642286439623. The next prime is 642286439687. The reversal of 642286439681 is 186934682246.

It is a happy number.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 617731549681 + 24554890000 = 785959^2 + 156700^2 .

It is a cyclic number.

It is not a de Polignac number, because 642286439681 - 2¹⁸ = 642286177537 is a prime.

It is a super-2 number, since 2×642286439681² (a number of 24 digits) contains 22 as substring.

It is a self number, because there is not a number n which added to its sum of digits gives 642286439681.

It is not a weakly prime, because it can be changed into another prime (642286439687) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 321143219840 + 321143219841.

It is an arithmetic number, because the mean of its divisors is an integer number (321143219841).

Almost surely, 2^642286439681 is an apocalyptic number.

It is an amenable number.

642286439681 is a deficient number, since it is larger than the sum of its proper divisors (1).

642286439681 is an equidigital number, since it uses as much as digits as its factorization.

642286439681 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 23887872, while the sum is 59.

The spelling of 642286439681 in words is "six hundred forty-two billion, two hundred eighty-six million, four hundred thirty-nine thousand, six hundred eighty-one".