1668355837 has 2 divisors, whose sum is σ = 1668355838. Its totient is φ = 1668355836.

The previous prime is 1668355823. The next prime is 1668355841. The reversal of 1668355837 is 7385538661.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 962178361 + 706177476 = 31019^2 + 26574^2 .

It is a cyclic number.

It is not a de Polignac number, because 1668355837 - 2¹⁹ = 1667831549 is a prime.

It is a super-2 number, since 2×1668355837² = 5566822397703941138, which contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (1668350837) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 834177918 + 834177919.

It is an arithmetic number, because the mean of its divisors is an integer number (834177919).

Almost surely, 2^1668355837 is an apocalyptic number.

It is an amenable number.

1668355837 is a deficient number, since it is larger than the sum of its proper divisors (1).

1668355837 is an equidigital number, since it uses as much as digits as its factorization.

1668355837 is an evil number, because the sum of its binary digits is even.

The product of its digits is 3628800, while the sum is 52.

The square root of 1668355837 is about 40845.5118342273. The cubic root of 1668355837 is about 1186.0315128311.

The spelling of 1668355837 in words is "one billion, six hundred sixty-eight million, three hundred fifty-five thousand, eight hundred thirty-seven".