6389640 has 48 divisors (see below), whose sum is σ = 20767500. Its totient is φ = 1703808.

The previous prime is 6389629. The next prime is 6389683. The reversal of 6389640 is 469836.

6389640 is a `hidden beast` number, since 6 + 3 + 8 + 9 + 640 = 666.

6389640 is digitally balanced in base 4, because in such base it contains all the possibile digits an equal number of times.

It can be written as a sum of positive squares in 2 ways, for example, as 5673924 + 715716 = 2382^2 + 846^2 .

It is a Harshad number since it is a multiple of its sum of digits (36).

It is a junction number, because it is equal to n+sod(n) for n = 6389595 and 6389604.

It is an unprimeable number.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 8515 + ... + 9234.

Almost surely, 2^6389640 is an apocalyptic number.

6389640 is a gapful number since it is divisible by the number (60) formed by its first and last digit.

It is an amenable number.

6389640 is an abundant number, since it is smaller than the sum of its proper divisors (14377860).

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

6389640 is a wasteful number, since it uses less digits than its factorization.

6389640 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 17766 (or 17759 counting only the distinct ones).

The product of its (nonzero) digits is 31104, while the sum is 36.

The square root of 6389640 is about 2527.7737240505. The cubic root of 6389640 is about 185.5633182809.

Subtracting from 6389640 its product of nonzero digits (31104), we obtain a palindrome (6358536).

It can be divided in two parts, 63896 and 40, that added together give a palindrome (63936).

The spelling of 6389640 in words is "six million, three hundred eighty-nine thousand, six hundred forty".