6647920 has 40 divisors (see below), whose sum is σ = 16132896. Its totient is φ = 2542848.

The previous prime is 6647917. The next prime is 6647923. The reversal of 6647920 is 297466.

It is an interprime number because it is at equal distance from previous prime (6647917) and next prime (6647923).

It is a tau number, because it is divible by the number of its divisors (40).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (6647923) 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, 34 + ... + 3646.

Almost surely, 2^6647920 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 6647920, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (8066448).

6647920 is an abundant number, since it is smaller than the sum of its proper divisors (9484976).

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

6647920 is a wasteful number, since it uses less digits than its factorization.

6647920 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3649 (or 3643 counting only the distinct ones).

The product of its (nonzero) digits is 18144, while the sum is 34.

The square root of 6647920 is about 2578.3560654029. The cubic root of 6647920 is about 188.0306272722.

The spelling of 6647920 in words is "six million, six hundred forty-seven thousand, nine hundred twenty".