16668338340691 has 2 divisors, whose sum is σ = 16668338340692. Its totient is φ = 16668338340690.

The previous prime is 16668338340631. The next prime is 16668338340713. The reversal of 16668338340691 is 19604383386661.

16668338340691 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 16668338340691 - 2¹¹ = 16668338338643 is a prime.

It is not a weakly prime, because it can be changed into another prime (16668338340631) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 8334169170345 + 8334169170346.

It is an arithmetic number, because the mean of its divisors is an integer number (8334169170346).

Almost surely, 2^{16668338340691} is an apocalyptic number.

16668338340691 is a deficient number, since it is larger than the sum of its proper divisors (1).

16668338340691 is an equidigital number, since it uses as much as digits as its factorization.

16668338340691 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 80621568, while the sum is 64.

The spelling of 16668338340691 in words is "sixteen trillion, six hundred sixty-eight billion, three hundred thirty-eight million, three hundred forty thousand, six hundred ninety-one".