668977 has 4 divisors (see below), whose sum is σ = 673396. Its totient is φ = 664560.

The previous prime is 668963. The next prime is 668989. The reversal of 668977 is 779866.

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 461041 + 207936 = 679^2 + 456^2 .

It is a cyclic number.

It is not a de Polignac number, because 668977 - 2¹¹ = 666929 is a prime.

It is a Duffinian number.

It is an inconsummate number, since it does not exist a number n which divided by its sum of digits gives 668977.

It is not an unprimeable number, because it can be changed into a prime (668947) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1974 + ... + 2287.

It is an arithmetic number, because the mean of its divisors is an integer number (168349).

2⁶⁶⁸⁹⁷⁷ is an apocalyptic number.

It is an amenable number.

668977 is a deficient number, since it is larger than the sum of its proper divisors (4419).

668977 is a wasteful number, since it uses less digits than its factorization.

668977 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4418.

The product of its digits is 127008, while the sum is 43.

The square root of 668977 is about 817.9101417638. The cubic root of 668977 is about 87.4588432294.

Subtracting 668977 from its reverse (779866), we obtain a square (110889 = 333²).

The spelling of 668977 in words is "six hundred sixty-eight thousand, nine hundred seventy-seven".