664481646 has 12 divisors (see below), whose sum is σ = 1439710272. Its totient is φ = 221493876.

The previous prime is 664481641. The next prime is 664481651. The reversal of 664481646 is 646184466.

It is an interprime number because it is at equal distance from previous prime (664481641) and next prime (664481651).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (664481641) 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 5 ways as a sum of consecutive naturals, for example, 18457806 + ... + 18457841.

It is an arithmetic number, because the mean of its divisors is an integer number (119975856).

Almost surely, 2^664481646 is an apocalyptic number.

664481646 is an abundant number, since it is smaller than the sum of its proper divisors (775228626).

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

664481646 is a wasteful number, since it uses less digits than its factorization.

664481646 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 36915655 (or 36915652 counting only the distinct ones).

The product of its digits is 663552, while the sum is 45.

The square root of 664481646 is about 25777.5415041854. The cubic root of 664481646 is about 872.6250244617.

The spelling of 664481646 in words is "six hundred sixty-four million, four hundred eighty-one thousand, six hundred forty-six".