6646864 has 40 divisors (see below), whose sum is σ = 15588288. Its totient is φ = 2680320.

The previous prime is 6646859. The next prime is 6646867. The reversal of 6646864 is 4686466.

6646864 = T₂₈₇ + T₂₈₈ + ... + T₃₉₈.

It is a Smith number, since the sum of its digits (40) coincides with the sum of the digits of its prime factors.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (6646867) 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, 159 + ... + 3649.

Almost surely, 2^6646864 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 6646864, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (7794144).

6646864 is an abundant number, since it is smaller than the sum of its proper divisors (8941424).

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

6646864 is a wasteful number, since it uses less digits than its factorization.

6646864 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3523 (or 3517 counting only the distinct ones).

The product of its digits is 165888, while the sum is 40.

The square root of 6646864 is about 2578.1512756237. The cubic root of 6646864 is about 188.0206707315.

The spelling of 6646864 in words is "six million, six hundred forty-six thousand, eight hundred sixty-four".