1666201043657 has 8 divisors (see below), whose sum is σ = 1684333168896. Its totient is φ = 1648164100752.

The previous prime is 1666201043621. The next prime is 1666201043669. The reversal of 1666201043657 is 7563401026661.

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 1666201043657 - 2¹⁰ = 1666201042633 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (1666201043557) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 23760383 + ... + 23830404.

It is an arithmetic number, because the mean of its divisors is an integer number (210541646112).

Almost surely, 2^{1666201043657} is an apocalyptic number.

It is an amenable number.

1666201043657 is a deficient number, since it is larger than the sum of its proper divisors (18132125239).

1666201043657 is a wasteful number, since it uses less digits than its factorization.

1666201043657 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 47591167.

The product of its (nonzero) digits is 1088640, while the sum is 47.

The spelling of 1666201043657 in words is "one trillion, six hundred sixty-six billion, two hundred one million, forty-three thousand, six hundred fifty-seven".