1556640343666 has 32 divisors (see below), whose sum is σ = 2483713964160. Its totient is φ = 730062013824.

The previous prime is 1556640343649. The next prime is 1556640343669. The reversal of 1556640343666 is 6663430466551.

It is not an unprimeable number, because it can be changed into a prime (1556640343669) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 4663486 + ... + 4986118.

It is an arithmetic number, because the mean of its divisors is an integer number (77616061380).

Almost surely, 2^{1556640343666} is an apocalyptic number.

1556640343666 is a deficient number, since it is larger than the sum of its proper divisors (927073620494).

1556640343666 is a wasteful number, since it uses less digits than its factorization.

1556640343666 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 324690.

The product of its (nonzero) digits is 27993600, while the sum is 55.

The spelling of 1556640343666 in words is "one trillion, five hundred fifty-six billion, six hundred forty million, three hundred forty-three thousand, six hundred sixty-six".