668752221 has 8 divisors (see below), whose sum is σ = 891799264. Its totient is φ = 445770000.

The previous prime is 668752207. The next prime is 668752223. The reversal of 668752221 is 122257866.

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 668752221 - 2⁹ = 668751709 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 668752221.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (668752223) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 18471 + ... + 40971.

It is an arithmetic number, because the mean of its divisors is an integer number (111474908).

Almost surely, 2^668752221 is an apocalyptic number.

It is an amenable number.

668752221 is a deficient number, since it is larger than the sum of its proper divisors (223047043).

668752221 is a wasteful number, since it uses less digits than its factorization.

668752221 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 32411.

The product of its digits is 80640, while the sum is 39.

The square root of 668752221 is about 25860.2440243707. The cubic root of 668752221 is about 874.4904662280.

It can be divided in two parts, 66875 and 2221, that added together give a palindrome (69096).

The spelling of 668752221 in words is "six hundred sixty-eight million, seven hundred fifty-two thousand, two hundred twenty-one".