1665564613556 has 6 divisors (see below), whose sum is σ = 2914738073730. Its totient is φ = 832782306776.

The previous prime is 1665564613523. The next prime is 1665564613613. The reversal of 1665564613556 is 6553164655661.

It can be written as a sum of positive squares in only one way, i.e., 1010258173456 + 655306440100 = 1005116^2 + 809510^2 .

It is a junction number, because it is equal to n+sod(n) for n = 1665564613495 and 1665564613504.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 208195576691 + ... + 208195576698.

It is an arithmetic number, because the mean of its divisors is an integer number (485789678955).

Almost surely, 2^{1665564613556} is an apocalyptic number.

It is an amenable number.

1665564613556 is a deficient number, since it is larger than the sum of its proper divisors (1249173460174).

1665564613556 is a wasteful number, since it uses less digits than its factorization.

1665564613556 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 416391153393 (or 416391153391 counting only the distinct ones).

The product of its digits is 58320000, while the sum is 59.

The spelling of 1665564613556 in words is "one trillion, six hundred sixty-five billion, five hundred sixty-four million, six hundred thirteen thousand, five hundred fifty-six".