15645661673 has 2 divisors, whose sum is σ = 15645661674. Its totient is φ = 15645661672.

The previous prime is 15645661667. The next prime is 15645661711. The reversal of 15645661673 is 37616654651.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 10347568729 + 5298092944 = 101723^2 + 72788^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-15645661673 is a prime.

It is a Sophie Germain prime.

It is a Curzon number.

It is not a weakly prime, because it can be changed into another prime (15645661613) 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, 7822830836 + 7822830837.

It is an arithmetic number, because the mean of its divisors is an integer number (7822830837).

Almost surely, 2^15645661673 is an apocalyptic number.

It is an amenable number.

15645661673 is a deficient number, since it is larger than the sum of its proper divisors (1).

15645661673 is an equidigital number, since it uses as much as digits as its factorization.

15645661673 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 2721600, while the sum is 50.

The spelling of 15645661673 in words is "fifteen billion, six hundred forty-five million, six hundred sixty-one thousand, six hundred seventy-three".