668644481 has 8 divisors (see below), whose sum is σ = 674476200. Its totient is φ = 662835712.

The previous prime is 668644421. The next prime is 668644489. The reversal of 668644481 is 184446866.

668644481 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It can be written as a sum of positive squares in 4 ways, for example, as 61465600 + 607178881 = 7840^2 + 24641^2 .

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

It is a cyclic number.

It is not a de Polignac number, because 668644481 - 2²² = 664450177 is a prime.

It is a super-2 number, since 2×668644481² = 894170883943518722, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (668644489) 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, 55595 + ... + 66543.

It is an arithmetic number, because the mean of its divisors is an integer number (84309525).

Almost surely, 2^668644481 is an apocalyptic number.

It is an amenable number.

668644481 is a deficient number, since it is larger than the sum of its proper divisors (5831719).

668644481 is a wasteful number, since it uses less digits than its factorization.

668644481 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 11475.

The product of its digits is 884736, while the sum is 47.

The square root of 668644481 is about 25858.1608201357. The cubic root of 668644481 is about 874.4435018168.

The spelling of 668644481 in words is "six hundred sixty-eight million, six hundred forty-four thousand, four hundred eighty-one".