665990664 has 32 divisors (see below), whose sum is σ = 1676160000. Its totient is φ = 220505792.

The previous prime is 665990659. The next prime is 665990669. The reversal of 665990664 is 466099566.

It is an interprime number because it is at equal distance from previous prime (665990659) and next prime (665990669).

It is not an unprimeable number, because it can be changed into a prime (665990669) by changing a digit.

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 7 ways as a sum of consecutive naturals, for example, 89544 + ... + 96695.

It is an arithmetic number, because the mean of its divisors is an integer number (52380000).

Almost surely, 2^665990664 is an apocalyptic number.

It is an amenable number.

665990664 is an abundant number, since it is smaller than the sum of its proper divisors (1010169336).

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

665990664 is a wasteful number, since it uses less digits than its factorization.

665990664 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 186397 (or 186393 counting only the distinct ones).

The product of its (nonzero) digits is 2099520, while the sum is 51.

The square root of 665990664 is about 25806.7949191681. The cubic root of 665990664 is about 873.2850935161.

The spelling of 665990664 in words is "six hundred sixty-five million, nine hundred ninety thousand, six hundred sixty-four".