66664646 has 16 divisors (see below), whose sum is σ = 101361888. Its totient is φ = 32880000.

The previous prime is 66664627. The next prime is 66664691. The reversal of 66664646 is 64646666.

It is a junction number, because it is equal to n+sod(n) for n = 66664597 and 66664606.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 80591 + ... + 81413.

It is an arithmetic number, because the mean of its divisors is an integer number (6335118).

Almost surely, 2^66664646 is an apocalyptic number.

66664646 is a deficient number, since it is larger than the sum of its proper divisors (34697242).

66664646 is a wasteful number, since it uses less digits than its factorization.

66664646 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1327.

The product of its digits is 746496, while the sum is 44.

The square root of 66664646 is about 8164.8420682828. The cubic root of 66664646 is about 405.4760362959.

The spelling of 66664646 in words is "sixty-six million, six hundred sixty-four thousand, six hundred forty-six".