1647297664 has 64 divisors (see below), whose sum is σ = 3422010240. Its totient is φ = 789175296.

The previous prime is 1647297629. The next prime is 1647297679. The reversal of 1647297664 is 4667927461.

It is a tau number, because it is divible by the number of its divisors (64).

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 288889 + ... + 294535.

It is an arithmetic number, because the mean of its divisors is an integer number (53468910).

Almost surely, 2^1647297664 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 1647297664, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1711005120).

1647297664 is an abundant number, since it is smaller than the sum of its proper divisors (1774712576).

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

1647297664 is an equidigital number, since it uses as much as digits as its factorization.

1647297664 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5757 (or 5745 counting only the distinct ones).

The product of its digits is 3048192, while the sum is 52.

The square root of 1647297664 is about 40586.9149357277. The cubic root of 1647297664 is about 1181.0202953626.

The spelling of 1647297664 in words is "one billion, six hundred forty-seven million, two hundred ninety-seven thousand, six hundred sixty-four".