664043688 has 288 divisors, whose sum is σ = 2324013120. Its totient is φ = 169344000.

The previous prime is 664043687. The next prime is 664043689. The reversal of 664043688 is 886340466.

It is an interprime number because it is at equal distance from previous prime (664043687) and next prime (664043689).

It is not an unprimeable number, because it can be changed into a prime (664043687) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 71 ways as a sum of consecutive naturals, for example, 2755248 + ... + 2755488.

It is an arithmetic number, because the mean of its divisors is an integer number (8069490).

Almost surely, 2^664043688 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 664043688, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1162006560).

664043688 is an abundant number, since it is smaller than the sum of its proper divisors (1659969432).

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

664043688 is a wasteful number, since it uses less digits than its factorization.

664043688 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 349 (or 335 counting only the distinct ones).

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

The square root of 664043688 is about 25769.0451511111. The cubic root of 664043688 is about 872.4332674199.

The spelling of 664043688 in words is "six hundred sixty-four million, forty-three thousand, six hundred eighty-eight".