647864 has 32 divisors (see below), whose sum is σ = 1451520. Its totient is φ = 265056.

The previous prime is 647861. The next prime is 647891. The reversal of 647864 is 468746.

647864 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a congruent number.

It is an inconsummate number, since it does not exist a number n which divided by its sum of digits gives 647864.

It is not an unprimeable number, because it can be changed into a prime (647861) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 1037 + ... + 1539.

It is an arithmetic number, because the mean of its divisors is an integer number (45360).

2⁶⁴⁷⁸⁶⁴ 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 647864, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (725760).

647864 is an abundant number, since it is smaller than the sum of its proper divisors (803656).

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

647864 is a wasteful number, since it uses less digits than its factorization.

647864 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 539 (or 535 counting only the distinct ones).

The product of its digits is 32256, while the sum is 35.

The square root of 647864 is about 804.8999937880. The cubic root of 647864 is about 86.5289199078.

The spelling of 647864 in words is "six hundred forty-seven thousand, eight hundred sixty-four".