1668668537 has 2 divisors, whose sum is σ = 1668668538. Its totient is φ = 1668668536.

The previous prime is 1668668501. The next prime is 1668668549. The reversal of 1668668537 is 7358668661.

It is a happy number.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 1433076736 + 235591801 = 37856^2 + 15349^2 .

It is a cyclic number.

It is not a de Polignac number, because 1668668537 - 2¹⁸ = 1668406393 is a prime.

It is not a weakly prime, because it can be changed into another prime (1668668737) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 834334268 + 834334269.

It is an arithmetic number, because the mean of its divisors is an integer number (834334269).

Almost surely, 2^1668668537 is an apocalyptic number.

It is an amenable number.

1668668537 is a deficient number, since it is larger than the sum of its proper divisors (1).

1668668537 is an equidigital number, since it uses as much as digits as its factorization.

1668668537 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 8709120, while the sum is 56.

The square root of 1668668537 is about 40849.3394928241. The cubic root of 1668668537 is about 1186.1056075131.

The spelling of 1668668537 in words is "one billion, six hundred sixty-eight million, six hundred sixty-eight thousand, five hundred thirty-seven".