668640125 has 8 divisors (see below), whose sum is σ = 834463032. Its totient is φ = 534912000.

The previous prime is 668640047. The next prime is 668640187. The reversal of 668640125 is 521046866.

It can be written as a sum of positive squares in 4 ways, for example, as 196056004 + 472584121 = 14002^2 + 21739^2 .

It is not a de Polignac number, because 668640125 - 2¹⁴ = 668623741 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 pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 2674436 + ... + 2674685.

It is an arithmetic number, because the mean of its divisors is an integer number (104307879).

Almost surely, 2^668640125 is an apocalyptic number.

It is an amenable number.

668640125 is a deficient number, since it is larger than the sum of its proper divisors (165822907).

668640125 is an equidigital number, since it uses as much as digits as its factorization.

668640125 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5349136 (or 5349126 counting only the distinct ones).

The product of its (nonzero) digits is 69120, while the sum is 38.

The square root of 668640125 is about 25858.0765912703. The cubic root of 668640125 is about 874.4416029083.

The spelling of 668640125 in words is "six hundred sixty-eight million, six hundred forty thousand, one hundred twenty-five".