1666065611661 has 8 divisors (see below), whose sum is σ = 2423368162464. Its totient is φ = 1009736734320.

The previous prime is 1666065611513. The next prime is 1666065611669. The reversal of 1666065611661 is 1661165606661.

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

It is not a de Polignac number, because 1666065611661 - 2¹³ = 1666065603469 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1666065611669) 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, 25243418326 + ... + 25243418391.

It is an arithmetic number, because the mean of its divisors is an integer number (302921020308).

Almost surely, 2^{1666065611661} is an apocalyptic number.

1666065611661 is a gapful number since it is divisible by the number (11) formed by its first and last digit.

It is an amenable number.

1666065611661 is a deficient number, since it is larger than the sum of its proper divisors (757302550803).

1666065611661 is a wasteful number, since it uses less digits than its factorization.

1666065611661 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 50486836731.

The product of its (nonzero) digits is 1399680, while the sum is 51.

The spelling of 1666065611661 in words is "one trillion, six hundred sixty-six billion, sixty-five million, six hundred eleven thousand, six hundred sixty-one".