664221684 has 192 divisors, whose sum is σ = 1961164800. Its totient is φ = 170698752.

The previous prime is 664221643. The next prime is 664221697. The reversal of 664221684 is 486122466.

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 63 ways as a sum of consecutive naturals, for example, 5230029 + ... + 5230155.

It is an arithmetic number, because the mean of its divisors is an integer number (10214400).

Almost surely, 2^664221684 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 664221684, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (980582400).

664221684 is an abundant number, since it is smaller than the sum of its proper divisors (1296943116).

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

664221684 is a wasteful number, since it uses less digits than its factorization.

664221684 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 302 (or 300 counting only the distinct ones).

The product of its digits is 110592, while the sum is 39.

The square root of 664221684 is about 25772.4985983121. The cubic root of 664221684 is about 872.5112119697.

The spelling of 664221684 in words is "six hundred sixty-four million, two hundred twenty-one thousand, six hundred eighty-four".