647838 has 48 divisors (see below), whose sum is σ = 1537536. Its totient is φ = 204120.

The previous prime is 647837. The next prime is 647839. The reversal of 647838 is 838746.

647838 is a `hidden beast` number, since 647 + 8 + 3 + 8 = 666.

It is an interprime number because it is at equal distance from previous prime (647837) and next prime (647839).

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 647838.

It is not an unprimeable number, because it can be changed into a prime (647837) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 15045 + ... + 15087.

It is an arithmetic number, because the mean of its divisors is an integer number (32032).

2⁶⁴⁷⁸³⁸ is an apocalyptic number.

It is a practical number, because each smaller number is the sum of distinct divisors of 647838, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (768768).

647838 is an abundant number, since it is smaller than the sum of its proper divisors (889698).

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

647838 is a wasteful number, since it uses less digits than its factorization.

647838 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 91 (or 79 counting only the distinct ones).

The product of its digits is 32256, while the sum is 36.

The square root of 647838 is about 804.8838425512. The cubic root of 647838 is about 86.5277623696.

It can be divided in two parts, 647 and 838, that added together give a triangular number (1485 = T₅₄).

The spelling of 647838 in words is "six hundred forty-seven thousand, eight hundred thirty-eight".