668405205 has 24 divisors (see below), whose sum is σ = 1247690808. Its totient is φ = 329060736.

The previous prime is 668405203. The next prime is 668405263. The reversal of 668405205 is 502504866.

It can be written as a sum of positive squares in 4 ways, for example, as 36687249 + 631717956 = 6057^2 + 25134^2 .

It is not a de Polignac number, because 668405205 - 2¹ = 668405203 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 668405205.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (668405203) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 570702 + ... + 571871.

It is an arithmetic number, because the mean of its divisors is an integer number (51987117).

Almost surely, 2^668405205 is an apocalyptic number.

668405205 is a gapful number since it is divisible by the number (65) formed by its first and last digit.

It is an amenable number.

668405205 is a deficient number, since it is larger than the sum of its proper divisors (579285603).

668405205 is a wasteful number, since it uses less digits than its factorization.

668405205 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1142597 (or 1142594 counting only the distinct ones).

The product of its (nonzero) digits is 57600, while the sum is 36.

The square root of 668405205 is about 25853.5337043121. The cubic root of 668405205 is about 874.3391821510.

The spelling of 668405205 in words is "six hundred sixty-eight million, four hundred five thousand, two hundred five".