668911205 has 4 divisors (see below), whose sum is σ = 802693452. Its totient is φ = 535128960.

The previous prime is 668911171. The next prime is 668911241. The reversal of 668911205 is 502119866.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 113507716 + 555403489 = 10654^2 + 23567^2 .

It is not a de Polignac number, because 668911205 - 2⁶ = 668911141 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 66891116 + ... + 66891125.

It is an arithmetic number, because the mean of its divisors is an integer number (200673363).

Almost surely, 2^668911205 is an apocalyptic number.

It is an amenable number.

668911205 is a deficient number, since it is larger than the sum of its proper divisors (133782247).

668911205 is a wasteful number, since it uses less digits than its factorization.

668911205 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 133782246.

The product of its (nonzero) digits is 25920, while the sum is 38.

The square root of 668911205 is about 25863.3177492757. The cubic root of 668911205 is about 874.5597589457.

The spelling of 668911205 in words is "six hundred sixty-eight million, nine hundred eleven thousand, two hundred five".