669721538341 has 2 divisors, whose sum is σ = 669721538342. Its totient is φ = 669721538340.

The previous prime is 669721538309. The next prime is 669721538359. The reversal of 669721538341 is 143835127966.

It is a happy number.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 666637957441 + 3083580900 = 816479^2 + 55530^2 .

It is a cyclic number.

It is not a de Polignac number, because 669721538341 - 2⁵ = 669721538309 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (669721532341) 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, 334860769170 + 334860769171.

It is an arithmetic number, because the mean of its divisors is an integer number (334860769171).

Almost surely, 2^669721538341 is an apocalyptic number.

It is an amenable number.

669721538341 is a deficient number, since it is larger than the sum of its proper divisors (1).

669721538341 is an equidigital number, since it uses as much as digits as its factorization.

669721538341 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 6531840, while the sum is 55.

The spelling of 669721538341 in words is "six hundred sixty-nine billion, seven hundred twenty-one million, five hundred thirty-eight thousand, three hundred forty-one".