1646993664 has 54 divisors (see below), whose sum is σ = 4748695406. Its totient is φ = 548997120.

The previous prime is 1646993641. The next prime is 1646993669. The reversal of 1646993664 is 4663996461.

It can be written as a sum of positive squares in only one way, i.e., 1459851264 + 187142400 = 38208^2 + 13680^2 .

It is a super-3 number, since 3×1646993664³ (a number of 29 digits) contains 333 as substring. Note that it is a super-d number also for d = 2.

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 1646993664.

It is not an unprimeable number, because it can be changed into a prime (1646993669) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 355117 + ... + 359724.

Almost surely, 2^1646993664 is an apocalyptic number.

It is an amenable number.

1646993664 is an abundant number, since it is smaller than the sum of its proper divisors (3101701742).

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

1646993664 is an equidigital number, since it uses as much as digits as its factorization.

1646993664 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 714863 (or 714846 counting only the distinct ones).

The product of its digits is 5038848, while the sum is 54.

The square root of 1646993664 is about 40583.1697135648. The cubic root of 1646993664 is about 1180.9476405604.

The spelling of 1646993664 in words is "one billion, six hundred forty-six million, nine hundred ninety-three thousand, six hundred sixty-four".