2003166557681 has 2 divisors, whose sum is σ = 2003166557682. Its totient is φ = 2003166557680.

The previous prime is 2003166557671. The next prime is 2003166557683. The reversal of 2003166557681 is 1867556613002.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 1151348314081 + 851818243600 = 1073009^2 + 922940^2 .

It is a cyclic number.

It is not a de Polignac number, because 2003166557681 - 2⁶ = 2003166557617 is a prime.

It is a super-2 number, since 2×2003166557681² (a number of 25 digits) contains 22 as substring.

Together with 2003166557683, it forms a pair of twin primes.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (2003166557683) 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, 1001583278840 + 1001583278841.

It is an arithmetic number, because the mean of its divisors is an integer number (1001583278841).

Almost surely, 2^{2003166557681} is an apocalyptic number.

It is an amenable number.

2003166557681 is a deficient number, since it is larger than the sum of its proper divisors (1).

2003166557681 is an equidigital number, since it uses as much as digits as its factorization.

2003166557681 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 1814400, while the sum is 50.

The spelling of 2003166557681 in words is "two trillion, three billion, one hundred sixty-six million, five hundred fifty-seven thousand, six hundred eighty-one".