665666650646 has 8 divisors (see below), whose sum is σ = 1025486461920. Its totient is φ = 323837830008.

The previous prime is 665666650637. The next prime is 665666650667. The reversal of 665666650646 is 646056666566.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a super-2 number, since 2×665666650646² (a number of 24 digits) contains 22 as substring.

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 3 ways as a sum of consecutive naturals, for example, 4497747566 + ... + 4497747713.

It is an arithmetic number, because the mean of its divisors is an integer number (128185807740).

Almost surely, 2^665666650646 is an apocalyptic number.

665666650646 is a deficient number, since it is larger than the sum of its proper divisors (359819811274).

665666650646 is a wasteful number, since it uses less digits than its factorization.

665666650646 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 8995495318.

The product of its (nonzero) digits is 167961600, while the sum is 62.

The spelling of 665666650646 in words is "six hundred sixty-five billion, six hundred sixty-six million, six hundred fifty thousand, six hundred forty-six".