1668668501 has 2 divisors, whose sum is σ = 1668668502. Its totient is φ = 1668668500.

The previous prime is 1668668467. The next prime is 1668668537. The reversal of 1668668501 is 1058668661.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 1663824100 + 4844401 = 40790^2 + 2201^2 .

It is an emirp because it is prime and its reverse (1058668661) is a distict prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-1668668501 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (1668668591) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 834334250 + 834334251.

It is an arithmetic number, because the mean of its divisors is an integer number (834334251).

Almost surely, 2^1668668501 is an apocalyptic number.

It is an amenable number.

1668668501 is a deficient number, since it is larger than the sum of its proper divisors (1).

1668668501 is an equidigital number, since it uses as much as digits as its factorization.

1668668501 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 414720, while the sum is 47.

The square root of 1668668501 is about 40849.3390521805. The cubic root of 1668668501 is about 1186.1055989834.

The spelling of 1668668501 in words is "one billion, six hundred sixty-eight million, six hundred sixty-eight thousand, five hundred one".