1642430959781 has 2 divisors, whose sum is σ = 1642430959782. Its totient is φ = 1642430959780.

The previous prime is 1642430959777. The next prime is 1642430959879. The reversal of 1642430959781 is 1879590342461.

It is a happy number.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 1640218104100 + 2212855681 = 1280710^2 + 47041^2 .

It is a cyclic number.

It is not a de Polignac number, because 1642430959781 - 2² = 1642430959777 is a prime.

It is a super-2 number, since 2×1642430959781² (a number of 25 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 1642430959781.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (1642430959751) 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, 821215479890 + 821215479891.

It is an arithmetic number, because the mean of its divisors is an integer number (821215479891).

It is a 1-persistent number, because it is pandigital, but 2⋅1642430959781 = 3284861919562 is not.

Almost surely, 2^{1642430959781} is an apocalyptic number.

It is an amenable number.

1642430959781 is a deficient number, since it is larger than the sum of its proper divisors (1).

1642430959781 is an equidigital number, since it uses as much as digits as its factorization.

1642430959781 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 13063680, while the sum is 59.

The spelling of 1642430959781 in words is "one trillion, six hundred forty-two billion, four hundred thirty million, nine hundred fifty-nine thousand, seven hundred eighty-one".