1666602731561 has 8 divisors (see below), whose sum is σ = 1724888563200. Its totient is φ = 1608371351440.

The previous prime is 1666602731543. The next prime is 1666602731581. The reversal of 1666602731561 is 1651372066661.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 1666602731561 - 2¹⁰ = 1666602730537 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (1666602731501) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 13550591 + ... + 13673028.

It is an arithmetic number, because the mean of its divisors is an integer number (215611070400).

Almost surely, 2^{1666602731561} is an apocalyptic number.

It is an amenable number.

1666602731561 is a deficient number, since it is larger than the sum of its proper divisors (58285831639).

1666602731561 is a wasteful number, since it uses less digits than its factorization.

1666602731561 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 27225759.

The product of its (nonzero) digits is 1632960, while the sum is 50.

The spelling of 1666602731561 in words is "one trillion, six hundred sixty-six billion, six hundred two million, seven hundred thirty-one thousand, five hundred sixty-one".