3666681467821 has 2 divisors, whose sum is σ = 3666681467822. Its totient is φ = 3666681467820.

The previous prime is 3666681467719. The next prime is 3666681467863. The reversal of 3666681467821 is 1287641866663.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 3617836047721 + 48845420100 = 1902061^2 + 221010^2 .

It is an emirp because it is prime and its reverse (1287641866663) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 3666681467821 - 2²³ = 3666673079213 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (3666681467021) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 1833340733910 + 1833340733911.

It is an arithmetic number, because the mean of its divisors is an integer number (1833340733911).

Almost surely, 2^{3666681467821} is an apocalyptic number.

It is an amenable number.

3666681467821 is a deficient number, since it is larger than the sum of its proper divisors (1).

3666681467821 is an equidigital number, since it uses as much as digits as its factorization.

3666681467821 is an evil number, because the sum of its binary digits is even.

The product of its digits is 83607552, while the sum is 64.

The spelling of 3666681467821 in words is "three trillion, six hundred sixty-six billion, six hundred eighty-one million, four hundred sixty-seven thousand, eight hundred twenty-one".