1780138302781 has 2 divisors, whose sum is σ = 1780138302782. Its totient is φ = 1780138302780.

The previous prime is 1780138302769. The next prime is 1780138302829. The reversal of 1780138302781 is 1872038310871.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 1515937162756 + 264201140025 = 1231234^2 + 514005^2 .

It is a cyclic number.

It is not a de Polignac number, because 1780138302781 - 2⁵ = 1780138302749 is a prime.

It is a super-2 number, since 2×1780138302781² (a number of 25 digits) contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (1780138302721) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 890069151390 + 890069151391.

It is an arithmetic number, because the mean of its divisors is an integer number (890069151391).

Almost surely, 2^{1780138302781} is an apocalyptic number.

It is an amenable number.

1780138302781 is a deficient number, since it is larger than the sum of its proper divisors (1).

1780138302781 is an equidigital number, since it uses as much as digits as its factorization.

1780138302781 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 451584, while the sum is 49.

The spelling of 1780138302781 in words is "one trillion, seven hundred eighty billion, one hundred thirty-eight million, three hundred two thousand, seven hundred eighty-one".