3998664587761 has 2 divisors, whose sum is σ = 3998664587762. Its totient is φ = 3998664587760.

The previous prime is 3998664587713. The next prime is 3998664587773. The reversal of 3998664587761 is 1677854668993.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 2066233753600 + 1932430834161 = 1437440^2 + 1390119^2 .

It is an emirp because it is prime and its reverse (1677854668993) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 3998664587761 - 2⁹ = 3998664587249 is a prime.

It is not a weakly prime, because it can be changed into another prime (3998664527761) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 1999332293880 + 1999332293881.

It is an arithmetic number, because the mean of its divisors is an integer number (1999332293881).

Almost surely, 2^{3998664587761} is an apocalyptic number.

It is an amenable number.

3998664587761 is a deficient number, since it is larger than the sum of its proper divisors (1).

3998664587761 is an equidigital number, since it uses as much as digits as its factorization.

3998664587761 is an evil number, because the sum of its binary digits is even.

The product of its digits is 3292047360, while the sum is 79.

The spelling of 3998664587761 in words is "three trillion, nine hundred ninety-eight billion, six hundred sixty-four million, five hundred eighty-seven thousand, seven hundred sixty-one".