1668516668501 has 2 divisors, whose sum is σ = 1668516668502. Its totient is φ = 1668516668500.

The previous prime is 1668516668461. The next prime is 1668516668519. The reversal of 1668516668501 is 1058666158661.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 1494628502500 + 173888166001 = 1222550^2 + 416999^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-1668516668501 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (1668516668591) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 834258334250 + 834258334251.

It is an arithmetic number, because the mean of its divisors is an integer number (834258334251).

Almost surely, 2^{1668516668501} is an apocalyptic number.

It is an amenable number.

1668516668501 is a deficient number, since it is larger than the sum of its proper divisors (1).

1668516668501 is an equidigital number, since it uses as much as digits as its factorization.

1668516668501 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 12441600, while the sum is 59.

The spelling of 1668516668501 in words is "one trillion, six hundred sixty-eight billion, five hundred sixteen million, six hundred sixty-eight thousand, five hundred one".