1663705281361 has 2 divisors, whose sum is σ = 1663705281362. Its totient is φ = 1663705281360.

The previous prime is 1663705281347. The next prime is 1663705281449. The reversal of 1663705281361 is 1631825073661.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 1637168871361 + 26536410000 = 1279519^2 + 162900^2 .

It is a cyclic number.

It is not a de Polignac number, because 1663705281361 - 2⁷ = 1663705281233 is a prime.

It is not a weakly prime, because it can be changed into another prime (1663702281361) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 831852640680 + 831852640681.

It is an arithmetic number, because the mean of its divisors is an integer number (831852640681).

Almost surely, 2^{1663705281361} is an apocalyptic number.

It is an amenable number.

1663705281361 is a deficient number, since it is larger than the sum of its proper divisors (1).

1663705281361 is an equidigital number, since it uses as much as digits as its factorization.

1663705281361 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 1088640, while the sum is 49.

The spelling of 1663705281361 in words is "one trillion, six hundred sixty-three billion, seven hundred five million, two hundred eighty-one thousand, three hundred sixty-one".