6397940 has 12 divisors (see below), whose sum is σ = 13435716. Its totient is φ = 2559168.

The previous prime is 6397921. The next prime is 6397949. The reversal of 6397940 is 497936.

Added to its reverse (497936) it gives a square (6895876 = 2626²).

It can be written as a sum of positive squares in 2 ways, for example, as 3701776 + 2696164 = 1924^2 + 1642^2 .

It is a junction number, because it is equal to n+sod(n) for n = 6397894 and 6397903.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (6397949) 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, 159929 + ... + 159968.

It is an arithmetic number, because the mean of its divisors is an integer number (1119643).

Almost surely, 2^6397940 is an apocalyptic number.

It is an amenable number.

6397940 is an abundant number, since it is smaller than the sum of its proper divisors (7037776).

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

6397940 is a wasteful number, since it uses less digits than its factorization.

6397940 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 319906 (or 319904 counting only the distinct ones).

The product of its (nonzero) digits is 40824, while the sum is 38.

The square root of 6397940 is about 2529.4149521184. The cubic root of 6397940 is about 185.6436310548.

Adding to 6397940 its reverse (497936), we get a square (6895876 = 2626²).

It can be divided in two parts, 6397 and 940, that added together give a palindrome (7337).

The spelling of 6397940 in words is "six million, three hundred ninety-seven thousand, nine hundred forty".