6381640 has 16 divisors (see below), whose sum is σ = 14358780. Its totient is φ = 2552640.

The previous prime is 6381619. The next prime is 6381643. The reversal of 6381640 is 461836.

It can be written as a sum of positive squares in 2 ways, for example, as 6220036 + 161604 = 2494^2 + 402^2 .

It is a junction number, because it is equal to n+sod(n) for n = 6381599 and 6381608.

It is not an unprimeable number, because it can be changed into a prime (6381643) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (7) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 79731 + ... + 79810.

Almost surely, 2^6381640 is an apocalyptic number.

It is an amenable number.

6381640 is an abundant number, since it is smaller than the sum of its proper divisors (7977140).

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

6381640 is a wasteful number, since it uses less digits than its factorization.

6381640 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 159552 (or 159548 counting only the distinct ones).

The product of its (nonzero) digits is 3456, while the sum is 28.

The square root of 6381640 is about 2526.1908083120. The cubic root of 6381640 is about 185.4858425272.

It can be divided in two parts, 6381 and 640, that added together give a triangular number (7021 = T₁₁₈).

The spelling of 6381640 in words is "six million, three hundred eighty-one thousand, six hundred forty".