668405533 has 2 divisors, whose sum is σ = 668405534. Its totient is φ = 668405532.

The previous prime is 668405527. The next prime is 668405561. The reversal of 668405533 is 335504866.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 424483609 + 243921924 = 20603^2 + 15618^2 .

It is a cyclic number.

It is not a de Polignac number, because 668405533 - 2²⁵ = 634851101 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (668405033) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 334202766 + 334202767.

It is an arithmetic number, because the mean of its divisors is an integer number (334202767).

Almost surely, 2^668405533 is an apocalyptic number.

It is an amenable number.

668405533 is a deficient number, since it is larger than the sum of its proper divisors (1).

668405533 is an equidigital number, since it uses as much as digits as its factorization.

668405533 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 259200, while the sum is 40.

The square root of 668405533 is about 25853.5400477381. The cubic root of 668405533 is about 874.3393251696.

The spelling of 668405533 in words is "six hundred sixty-eight million, four hundred five thousand, five hundred thirty-three".