664821171156 has 72 divisors (see below), whose sum is σ = 1598341473792. Its totient is φ = 215068812800.

The previous prime is 664821171059. The next prime is 664821171169. The reversal of 664821171156 is 651171128466.

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 23 ways as a sum of consecutive naturals, for example, 3766576 + ... + 3939128.

It is an arithmetic number, because the mean of its divisors is an integer number (22199187136).

Almost surely, 2^664821171156 is an apocalyptic number.

It is an amenable number.

664821171156 is an abundant number, since it is smaller than the sum of its proper divisors (933520302636).

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

664821171156 is a wasteful number, since it uses less digits than its factorization.

664821171156 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 172833 (or 172790 counting only the distinct ones).

The product of its digits is 483840, while the sum is 48.

The spelling of 664821171156 in words is "six hundred sixty-four billion, eight hundred twenty-one million, one hundred seventy-one thousand, one hundred fifty-six".