660644406 has 12 divisors (see below), whose sum is σ = 1431396252. Its totient is φ = 220214796.

The previous prime is 660644401. The next prime is 660644431. The reversal of 660644406 is 604446066.

It is a happy number.

660644406 is a `hidden beast` number, since 6 + 6 + 0 + 644 + 4 + 0 + 6 = 666.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (660644401) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 18351216 + ... + 18351251.

It is an arithmetic number, because the mean of its divisors is an integer number (119283021).

Almost surely, 2^660644406 is an apocalyptic number.

660644406 is an abundant number, since it is smaller than the sum of its proper divisors (770751846).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

660644406 is a wasteful number, since it uses less digits than its factorization.

660644406 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 36702475 (or 36702472 counting only the distinct ones).

The product of its (nonzero) digits is 82944, while the sum is 36.

The square root of 660644406 is about 25703.0038322372. The cubic root of 660644406 is about 870.9420394372.

The spelling of 660644406 in words is "six hundred sixty million, six hundred forty-four thousand, four hundred six".