6394640 has 80 divisors (see below), whose sum is σ = 17915520. Its totient is φ = 2073600.

The previous prime is 6394637. The next prime is 6394643. The reversal of 6394640 is 464936.

It is an interprime number because it is at equal distance from previous prime (6394637) and next prime (6394643).

It is a tau number, because it is divible by the number of its divisors (80).

It is a junction number, because it is equal to n+sod(n) for n = 6394597 and 6394606.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (6394643) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 10340 + ... + 10940.

It is an arithmetic number, because the mean of its divisors is an integer number (223944).

Almost surely, 2^6394640 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 6394640, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (8957760).

6394640 is an abundant number, since it is smaller than the sum of its proper divisors (11520880).

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

6394640 is a wasteful number, since it uses less digits than its factorization.

6394640 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 640 (or 634 counting only the distinct ones).

The product of its (nonzero) digits is 15552, while the sum is 32.

The square root of 6394640 is about 2528.7625432215. The cubic root of 6394640 is about 185.6117077930.

The spelling of 6394640 in words is "six million, three hundred ninety-four thousand, six hundred forty".