665782656 has 384 divisors, whose sum is σ = 2344204800. Its totient is φ = 163553280.

The previous prime is 665782639. The next prime is 665782673. The reversal of 665782656 is 656287566.

It is an interprime number because it is at equal distance from previous prime (665782639) and next prime (665782673).

It is a tau number, because it is divible by the number of its divisors (384).

Its product of digits (3628800) is a multiple of the sum of its prime divisors (135).

It is a junction number, because it is equal to n+sod(n) for n = 665782599 and 665782608.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 7480660 + ... + 7480748.

It is an arithmetic number, because the mean of its divisors is an integer number (6104700).

Almost surely, 2^665782656 is an apocalyptic number.

665782656 is a gapful number since it is divisible by the number (66) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 665782656, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1172102400).

665782656 is an abundant number, since it is smaller than the sum of its proper divisors (1678422144).

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

665782656 is a wasteful number, since it uses less digits than its factorization.

665782656 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 158 (or 135 counting only the distinct ones).

The product of its digits is 3628800, while the sum is 51.

The square root of 665782656 is about 25802.7645030528. The cubic root of 665782656 is about 873.1941667157.

It can be divided in two parts, 66 and 5782656, that multiplied together give a square (381655296 = 19536²).

The spelling of 665782656 in words is "six hundred sixty-five million, seven hundred eighty-two thousand, six hundred fifty-six".