664776 has 48 divisors (see below), whose sum is σ = 2059200. Its totient is φ = 189792.

The previous prime is 664771. The next prime is 664777. The reversal of 664776 is 677466.

664776 is a `hidden beast` number, since 6 + 647 + 7 + 6 = 666.

It is a Harshad number since it is a multiple of its sum of digits (36).

It is a nude number because it is divisible by every one of its digits.

It is a self number, because there is not a number n which added to its sum of digits gives 664776.

It is not an unprimeable number, because it can be changed into a prime (664771) by changing a digit.

664776 is an untouchable number, because it is not equal to the sum of proper divisors of any number.

It is a pernicious number, because its binary representation contains a prime number (7) of ones.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 156 + ... + 1163.

It is an arithmetic number, because the mean of its divisors is an integer number (42900).

2⁶⁶⁴⁷⁷⁶ 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 664776, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1029600).

664776 is an abundant number, since it is smaller than the sum of its proper divisors (1394424).

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

664776 is a wasteful number, since it uses less digits than its factorization.

664776 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1338 (or 1331 counting only the distinct ones).

The product of its digits is 42336, while the sum is 36.

The square root of 664776 is about 815.3379667353. The cubic root of 664776 is about 87.2753858092.

The spelling of 664776 in words is "six hundred sixty-four thousand, seven hundred seventy-six".