647646 has 8 divisors (see below), whose sum is σ = 1295304. Its totient is φ = 215880.

The previous prime is 647641. The next prime is 647651. The reversal of 647646 is 646746.

It is an interprime number because it is at equal distance from previous prime (647641) and next prime (647651).

It is a sphenic number, since it is the product of 3 distinct primes.

647646 is an admirable number.

It is a Curzon number.

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 647646.

It is not an unprimeable number, because it can be changed into a prime (647641) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 53965 + ... + 53976.

It is an arithmetic number, because the mean of its divisors is an integer number (161913).

2⁶⁴⁷⁶⁴⁶ is an apocalyptic number.

647646 is a primitive abundant number, since it is smaller than the sum of its proper divisors, none of which is abundant.

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

647646 is a wasteful number, since it uses less digits than its factorization.

647646 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 107946.

The product of its digits is 24192, while the sum is 33.

The square root of 647646 is about 804.7645618440. The cubic root of 647646 is about 86.5192134361.

Subtracting from 647646 its reverse (646746), we obtain a square (900 = 30²).

The spelling of 647646 in words is "six hundred forty-seven thousand, six hundred forty-six".