668764672 has 20 divisors (see below), whose sum is σ = 1336224186. Its totient is φ = 334382080.

The previous prime is 668764667. The next prime is 668764673. The reversal of 668764672 is 276467866.

It is a happy number.

It can be written as a sum of positive squares in only one way, i.e., 412252416 + 256512256 = 20304^2 + 16016^2 .

It is not an unprimeable number, because it can be changed into a prime (668764673) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 652579 + ... + 653602.

Almost surely, 2^668764672 is an apocalyptic number.

It is an amenable number.

668764672 is a deficient number, since it is larger than the sum of its proper divisors (667459514).

668764672 is an equidigital number, since it uses as much as digits as its factorization.

668764672 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1306199 (or 1306183 counting only the distinct ones).

The product of its digits is 4064256, while the sum is 52.

The square root of 668764672 is about 25860.4847595709. The cubic root of 668764672 is about 874.4958933568.

The spelling of 668764672 in words is "six hundred sixty-eight million, seven hundred sixty-four thousand, six hundred seventy-two".