668660845 has 4 divisors (see below), whose sum is σ = 802393020. Its totient is φ = 534928672.

The previous prime is 668660843. The next prime is 668660849. The reversal of 668660845 is 548066866.

It is a happy number.

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 337493641 + 331167204 = 18371^2 + 18198^2 .

It is a cyclic number.

It is not a de Polignac number, because 668660845 - 2¹ = 668660843 is a prime.

It is a super-2 number, since 2×668660845² = 894214651272228050, which contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (668660843) by changing a digit.

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 3 ways as a sum of consecutive naturals, for example, 66866080 + ... + 66866089.

It is an arithmetic number, because the mean of its divisors is an integer number (200598255).

Almost surely, 2^668660845 is an apocalyptic number.

It is an amenable number.

668660845 is a deficient number, since it is larger than the sum of its proper divisors (133732175).

668660845 is a wasteful number, since it uses less digits than its factorization.

668660845 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 133732174.

The product of its (nonzero) digits is 1658880, while the sum is 49.

The square root of 668660845 is about 25858.4772366820. The cubic root of 668660845 is about 874.4506352921.

The spelling of 668660845 in words is "six hundred sixty-eight million, six hundred sixty thousand, eight hundred forty-five".