1605712008181 has 2 divisors, whose sum is σ = 1605712008182. Its totient is φ = 1605712008180.

The previous prime is 1605712008169. The next prime is 1605712008203. The reversal of 1605712008181 is 1818002175061.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 1210814136900 + 394897871281 = 1100370^2 + 628409^2 .

It is an emirp because it is prime and its reverse (1818002175061) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 1605712008181 - 2⁵ = 1605712008149 is a prime.

It is a super-2 number, since 2×1605712008181² (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 (1605712008161) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 802856004090 + 802856004091.

It is an arithmetic number, because the mean of its divisors is an integer number (802856004091).

Almost surely, 2^{1605712008181} is an apocalyptic number.

It is an amenable number.

1605712008181 is a deficient number, since it is larger than the sum of its proper divisors (1).

1605712008181 is an equidigital number, since it uses as much as digits as its factorization.

1605712008181 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 26880, while the sum is 40.

The spelling of 1605712008181 in words is "one trillion, six hundred five billion, seven hundred twelve million, eight thousand, one hundred eighty-one".