3661664663849 has 2 divisors, whose sum is σ = 3661664663850. Its totient is φ = 3661664663848.

The previous prime is 3661664663843. The next prime is 3661664663851. The reversal of 3661664663849 is 9483664661663.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 2551265063824 + 1110399600025 = 1597268^2 + 1053755^2 .

It is an emirp because it is prime and its reverse (9483664661663) is a distict prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-3661664663849 is a prime.

It is a super-2 number, since 2×3661664663849² (a number of 26 digits) contains 22 as substring.

Together with 3661664663851, 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 (3661664663843) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 1830832331924 + 1830832331925.

It is an arithmetic number, because the mean of its divisors is an integer number (1830832331925).

Almost surely, 2^{3661664663849} is an apocalyptic number.

It is an amenable number.

3661664663849 is a deficient number, since it is larger than the sum of its proper divisors (1).

3661664663849 is an equidigital number, since it uses as much as digits as its factorization.

3661664663849 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 483729408, while the sum is 68.

The spelling of 3661664663849 in words is "three trillion, six hundred sixty-one billion, six hundred sixty-four million, six hundred sixty-three thousand, eight hundred forty-nine".