16668688686661 has 24 divisors (see below), whose sum is σ = 18429450504192. Its totient is φ = 15064320823200.

The previous prime is 16668688686547. The next prime is 16668688686677.

16668688686661 is nontrivially palindromic in base 10.

It is not a de Polignac number, because 16668688686661 - 2²¹ = 16668686589509 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (16668688686061) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 261860940 + ... + 261924586.

It is an arithmetic number, because the mean of its divisors is an integer number (767893771008).

Almost surely, 2^{16668688686661} is an apocalyptic number.

16668688686661 is a gapful number since it is divisible by the number (11) formed by its first and last digit.

It is an amenable number.

16668688686661 is a deficient number, since it is larger than the sum of its proper divisors (1760761817531).

16668688686661 is a wasteful number, since it uses less digits than its factorization.

16668688686661 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 76353 (or 76342 counting only the distinct ones).

The product of its digits is 6879707136, while the sum is 82.

The spelling of 16668688686661 in words is "sixteen trillion, six hundred sixty-eight billion, six hundred eighty-eight million, six hundred eighty-six thousand, six hundred sixty-one".